N-alkyl-2-phenoxyethanamines, their preparation and use

ABSTRACT

The present invention provides a compound having the structure: (structurally represented) wherein R1, R2, R3, R4, and R5 are each independently H, halogen, CF3 or C1-C4 alkyl; R6 is alkyl; A is absent or present, and when present is —C(O)— or —C(O)NH—; B is substituted or unsubstituted monocycle, bicycle, heteromonocycle, heterobicycle, benzyl, CO2H or (C1-C4 alkyl)-CO2H, wherein when B is CO2H, then A is present and is —C(O)—, or a pharmaceutically acceptable salt thereof.

This application is a § 371 national stage of PCT International Application No. PCT/US2014/026730, filed Mar. 13, 2014, claiming the benefit of U.S. Provisional Application No. 61/785,415, filed Mar. 14, 2013, the contents of each of which are hereby incorporated by reference in their entirety.

The invention was made with government support under Grant numbers NS067594 and NS074476 awarded by the National Institutes of Health. The government has certain rights in the invention.

Throughout this application, certain publications are referenced in parentheses. Full citations for these publications may be found immediately preceding the claims. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to describe more fully the state of the art to which this invention relates.

BACKGROUND OF THE INVENTION

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. It is estimated that 62.9 million individuals worldwide have the most prevalent atrophic (dry) form of AMD; 8 million of them are Americans. Due to increasing life expectancy and current demographics this number is expected to triple by 2020. There is currently no FDA-approved treatment for dry AMD. Given the lack of treatment and high prevalence, development of drugs for dry AMD is of upmost importance. Clinically, atrophic AMD represents a slowly progressing neurodegenerative disorder in which specialized neurons (rod and cone photoreceptors) die in the central part of the retina called macula (1). Histopathological and clinical imaging studies indicate that photoreceptor degeneration in dry AMD is triggered by abnormalities in the retinal pigment epithelium (RPE) that lies beneath photoreceptors and provides critical metabolic support to these light-sensing neuronal cells.

Experimental and clinical data indicate that excessive accumulation of cytotoxic autofluorescent lipid-protein-retinoid aggregates (lipofuscin) in the RPE is a major trigger of dry AMD (2-9). In addition to AMD, dramatic accumulation of lipofuscin is the hallmark of Stargardt Disease (STGD), an inherited form of juvenile-onset macular degeneration. The major cytotoxic component of RPE lipofuscin is pyridinium bisretinoid A2E (FIG. 1). Additional cytotoxic bisretinoids are isoA2E, atRAL di-PE, and A2-DHP-PE (40, 41). Formation of A2E and other lipofuscin bisretinoids, such as A2-DHP-PE (A2-dihydropyridine-phosphatidylethanolamine) and atRALdi-PE (all-trans-retinal dimer-phosphatidylethanolamine), begins in photoreceptor cells in a non-enzymatic manner and can be considered as a by-product of the properly functioning visual cycle.

A2E is a product of condensation of all-trans retinaldehyde with phosphatidyl-ethanolamine which occurs in the retina in a non-enzymatic manner and, as illustrated in FIG. 4, can be considered a by-product of a properly functioning visual cycle (10). Light-induced isomerization of 11-cis retinaldehyde to its all-trans form is the first step in a signaling cascade that mediates light perception. The visual cycle is a chain of biochemical reactions that regenerate visual pigment (11-cis retinaldehyde conjugated to opsin) following exposure to light.

As cytotoxic bisretinoids are formed during the course of a normally functioning visual cycle, partial pharmacological inhibition of the visual cycle may represent a treatment strategy for dry AMD and other disorders characterized by excessive accumulation of lipofuscin (25-27, 40, 41).

SUMMARY OF THE INVENTION

The present invention provides a compound having the structure:

wherein R₁, R₂, R₃, R₄, and R₅ are each independently H, halogen, CF₃ or C₁-C₄ alkyl; R₆ is alkyl;

A is absent or present, and when present is

B is substituted or unsubstituted monocycle, bicycle, heteromonocycle, heterobicycle, benzyl, CO₂H or (C₁-C₄ alkyl)-CO₂H,

-   -   wherein when B is CO₂H, then A is present and is

or a pharmaceutically acceptable salt thereof.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1. Structure of bisretinoid A2E, a cytotoxic component of retinal lipofuscin.

FIG. 2. Structure of bisretinoid atRAL di-PE (all-transretinal dimer-phosphatidyl ethanolamine), a cytotoxiccomponent of retinal lipofuscin. R1 and R2 refer to various fatty acid constituents.

FIG. 3. Structure of bisretinoid A2-DHP-PE, a cytotoxic component of retinal lipofuscin.

FIG. 4. Visual cycle and biosynthesis of A2E. A2E biosynthesis begins when a portion of all-trans-retinal escapes the visual cycle (yellow box) and non-enzymatically reacts with phosphatidyl-ethanolamine forming the A2E precursor, A2-PE. Uptake of serum retinol to the RPE (gray box) fuels the cycle.

FIG. 5. Three-dimensional structure of the RBP4-TTR-retinol complex. Tetrameic TTR is shown in blue, light blue, green and yellow (large boxed region). RBP is shown in red (unboxed region) and retinol is shown in gray (small boxed region) (28).

FIG. 6. Structure of fenretinide, [N-(4-hydroxy-phenyl)retinamide, 4HRP], a retinoid RBP4 antagonist.

FIG. 7. Schematic depiction of the HTRF-based assay format for characterization of RBP4 antagonists disrupting retinol-induced RBP4-TTR interaction.

FIG. 8. RBP4 Binding, RBP4-TTR Interaction and/or Pharmacokinetic Data of compounds 11-14 and 19-34. PPB: Plasma protein binding, H: Human, M: Mouse, R: Rat, D: Dog.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a compound having the structure:

wherein R₁, R₂, R₃, R₄, and R₅ are each independently H, halogen, CF₃ or C₁-C₄ alkyl; R₆ is alkyl;

A is absent or present, and when present is

B is substituted or unsubstituted monocycle, bicycle, heteromonocycle, heterobicycle, benzyl, CO₂H or (C₁-C₄ alkyl)-CO₂H,

-   -   wherein when B is CO₂H, then A is present and is

or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound having the structure:

In some embodiments, the compound wherein B is a substituted or unsubstituted heterobicycle.

6 In some embodiments, the compound wherein B has the structure:

wherein α, β, χ, and δ are each independently absent or present, and when present each is a bond; X is C or N; Z₁ is S, O, or N; Z₂ is S, O, N or NH₇,

-   -   wherein R₇ is H, C₁-C₄ alkyl, or oxetane;         Q is a substituted or unsubstituted 5, 6, or 7 membered ring         structure.

In some embodiments of the above compound, the compound wherein B has the structure:

wherein when α is present, then Z₁ and Z₂ are N, X is N, β is present, and χ and δ are absent, or when α is present, then Z₁ is O or S, Z₂ is N, X is C, χ is present, and β and δ are absent; when α is absent, then Z₁ is N, Z₂ is N—R₇, X is C, β and δ are present, and χ is absent, or when α is absent, then Z₁ is N, Z₂ is O or S, X is C, β and δ are present, and χ is absent.

In some embodiments, the compound wherein B has the structure:

wherein n is an integer from 0-2; α, β, χ, δ, ϵ, and φ are each independently absent or present, and when present each is a bond; Z₁ is S, O or N; Z₂ is S, O, N or N—R₇,

-   -   wherein R₇ is H, C₁-C₁₀ alkyl, or oxetane;         X is C or N;         Y₁, Y₂, Y₃, and each occurrence of Y₄ are each independently         CR₈, C(R₉)₂, N—R₁₀, O, N, SO₂, or C═O,     -   wherein     -   R₈ is H, halogen, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl, O—(C₁-C₁₀         alkyl), C(O)OH, C(O)O(C₁-C₁₀ alkyl), C(O)—N₂, C(O)—NH(C₁-C₄         alkyl), C(O)—NH(C₁-C₄ alkyl)₂, NHC(O)—NH(C₁-C₁₀ alkyl),         NHC(O)—N(C₁-C₄ alkyl)₂, SO₂—NH(C₁-C₁₀ alkyl), SO₂—N(C₁-C₁₀         alkyl)₂, CN, or CF₃;     -   R₉ is H or C₁-C₁₀ alkyl;     -   R₁₀ is H, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl, (C₁-C₁₀ alkyl)-CF₃,         (C₁-C₁₀ alkyl)-OCH₃, (C₁-C₁₀ alkyl)-halogen, SO₂—(C₁-C₁₀ alkyl),         SO₂—(C₁-C₁₀ alkyl)-CF₃, SO₂—(C₁-C₁₀ alkyl)-OCH₃, SO₂—(C₁-C₁₀         alkyl)-halogen, C(O)—(C₁-C₁₀ alkyl), C(O)—(C₁-C₁₀ alkyl)-CF₃,         C(O)—(C₁-C₁₀ alkyl)-OCH₃, C(O)—(C₁-C₁₀ alkyl)-halogen,         C(O)—NH—(C₁-C₁₀ alkyl), C(O)—N(C₁-C₄ alkyl)₂, (C₁-C₁₀         alkyl)-C(O)OH, C(O)—NH₂ or oxetane.

In some embodiments of the above compound, the compound wherein B has the structure:

wherein when α is present, then Z₁ and Z₂ are N, X is N, β is present, and χ and δ are absent, or when α is present, then Z₁ is O or S, Z₂ is N, X is C, χ is present, and β and δ are absent; when α is absent, then Z₁ is N, Z₂ is N—R₇, X is C, β and δ are present, and χ is absent, or when α is absent, then Z₁ is N, Z₂ is O or S, X is C, β and δ are present, and χ is absent. when ϵ and φ are each present, then n=1, and each of Y₁, Y₂, Y₃, and Y₄ are independently C—R₈ or N; when ϵ and φ are each absent, then n=0, 1 or 2, each of Y₁, Y₂, Y₃, and each occurrence of Y₄ are independently C(R₉)₂, N—R₁₀, O, or SO₂.

In some embodiments, the compound wherein

-   -   β and δ are present;     -   α, χ, ϵ, and φ absent;     -   Z₁ is N;     -   Z₂ is O, S, or N—R₇,         -   wherein R₇ is H, C₁-C₄ alkyl, or oxetane; and     -   X is C.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 0;     -   R₇ is H, C₁-C₄ alkyl, or oxetane;     -   Y₁ and Y₃ are each CH₂ or C(CH₃)₂; and     -   Y₂ is O, SO₂, or N—R₁₀,         -   wherein         -   R₁₀ is H, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, (C₁-C₄ alkyl)-CF₃,             (C₁-C₄ alkyl)-OCH₃, (C₁-C₄ alkyl)-halogen, SO₂—(C₁-C₄             alkyl), SO₂—(C₁-C₄ alkyl)-CF₃, SO₂—(C₁-C₄ alkyl)-OCH₃,             SO₂—(C₁-C₄ alkyl)-halogen, C(O)—(C₁-C₄ alkyl), C(O)—(C₁-C₄             alkyl)-CF₃, C(O)—(C₁-C₄ alkyl)-OCH₃, C(O)—(C₁-C₄             alkyl)-halogen, C(O)—NH—(C₁-C₄ alkyl), C(O)—N(C₁-C₄ alkyl)₂,             (C₁-C₄ alkyl)-C(O)OH, C(O)—NH₂ or oxetane.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1;     -   R₇ is H, C₁-C₄ alkyl, or oxetane;     -   Y₁, Y₂ and Y₄ are each CH₂ or C(CH₃)₂; and     -   Y₃ is O, SO₂, or N—R₁₀,         -   wherein         -   R₁₀ is H, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, alkyl)-CF₃, (C₁-C₄             alkyl)-OCH₃, (C₁-C₄ alkyl)-halogen, SO₂—(C₁-C₄ alkyl),             SO₂—(C₁-C₄ alkyl)-CF₃, SO₂—(C₁-C₄ alkyl)-OCH₃, SO₂—(C₁-C₄             alkyl)-halogen, C(O)—(C₁-C₄ alkyl), C(O)—(C₁-C₄ alkyl)-CF₃,             C(O)—(C₁-C₄ alkyl)-OCH₃, C(O)—(C₁-C₄ alkyl)-halogen,             C(O)—NH—(C₁-C₄ alkyl), C(O)—N(C₁-C₄ alkyl)₂, (C₁-C₄             alkyl)-C(O)OH, C(O)—NH₂ or oxetane.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1;     -   R₇ is H, C₁-C₄ alkyl, or oxetane;     -   Y₁, Y₃ and Y₄ are each CH₂ or C(CH₃)₂; and     -   Y₂ is O, SO₂, or N—R₁₀,         -   wherein         -   R₁₀ is H, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, (C₁-C₄ alkyl)-CF₃,             (C₁-C₄ alkyl)-OCH₃, (C₁-C₄ alkyl)-halogen, SO₂—(C₁-C₄             alkyl), SO₂—(C₁-C₄ alkyl)-CF₃, SO₂—(C₁-C₄ alkyl)-OCH₃,             SO₂—(C₁-C₄ alkyl)-halogen, C(O)—(C₁-C₄ alkyl), C(O)—(C₁-C₄             alkyl)-CF₃, C(O)—(C₁-C₄ alkyl)-OCH₃, C(O)—(C₁-C₄             alkyl)-halogen, C(O)—NH—(C₁-C₄ alkyl), C(O)—N(C₁-C₄ alkyl)₂,             (C₁-C₄ alkyl)-C(O)OH, C(O)—NH₂ or oxetane.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 2;     -   R₇ is H, C₁-C₄ alkyl, or oxetane;     -   Y₁, Y₃ and each occurrence of Y₄ are each CH₂ or C(CH₃)₂; and     -   Y₂ is O, SO₂, or N—R₁₀,         -   wherein         -   R₁₀ is H, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, (C₁-C₄ alkyl)-CF₃,             (C₁-C₄ alkyl)-OCH₃, (C₁-C₄ alkyl)-halogen, SO₂—(C₁-C₄             alkyl), SO₂—(C₄-C₄ alkyl)-CF₃, SO₂—(C₁-C₄ alkyl)-OCH₃,             SO₂—(C₁-C₄ alkyl)-halogen, C(O)—(C₁-C₄ alkyl), C(O)—(C₁-C₄             alkyl)-CF₃, C(O)—(C₁-C₄ alkyl)-OCH₃, C(O)—(C₁-C₄             alkyl)-halogen, C(O)—NH—(C₁-C₄ alkyl), C(O)—N(C₁-C₄ alkyl)₂,             (C₁-C₄ alkyl)-C(O)OH, C(O)—NH₂ or oxetane.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound

-   -   wherein R₁₀ is H, CH₃, CH₂CH₃, CH₂CH₂CH₃, CH(CH₃)₂, CH₂CH(CH₃)₂,         t-Bu, CH₂OCH₃, CH₂CF₃, CH₂Cl, CH₂F, CH₂CH₂OCH₃, CH₂CH₂CF₃,         CH₂CH₂Cl, CH₂CH₂F, or

In some embodiments, the compound

-   -   wherein R₁₀ is SO₂—CH₃, SO₂—CH₂CH₃, SO₂—CH₂CH₂CH₃, SO₃—CH(CH₃)₂,         SO₂—CH₂CH(CH₃)₂, SO₂-t-Bu, SO₂—CH₂OCH₃, SO₂—CH₂CF₃, SO₂—CH₂Cl,         SO₂—CH₂F, SO₂—CH₂CH₂OCH₃, SO₂—CH₂CH₂CF₃, SO₂—CH₂CH₂Cl,         SO₂—CH₂CH₂F, or

In some embodiments, the compound

-   -   wherein R₁₀ is C(O)—CH₃, C(O)—CH₂CH₃, C(O)—CH₂CH₂CH₃,         C(O)—CH(CH₃)₂, C(O)—CH₂CH(CH₃)₂, C(O)-t-Bu, C(O)—CH₂OCH₃,         C(O)—CH₂CF₃, C(O)—CH₂Cl, C(O)—CH₂F, C(O)—CH₂CH₂OCH₃,         C(O)—CH₂CH₂CF₃, C(O)—CH₂CH₂Cl, C(O)—CH₂CH₂F,

In some embodiments, the compound wherein B has the structure:

20. The compound of claim 19,

-   -   wherein     -   R₇ is H, CH₃, CH₂CH₃, CH(CH₃)₂, or

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1;     -   R₇ is H, C₁-C₄ alkyl, or oxetane;     -   Y₁ and Y₄ are each CH₂; and     -   Y₂ is C═O and Y₃ is N—R₁₀, or Y₃ is C═O and Y₂ is N—R₁₀,         -   wherein         -   R₁₀ is H or C₁-C₄ alkyl.

22 In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein

-   -   R₇ is H, CH₃, CH₂CH₃, CH(CH₃)₂, or

and

-   -   each R₁₀ is H or CH₃.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1;     -   Y₁ and Y₄ are each CH₂; and     -   one of Y₂ or Y₃ is CH₂ and the other of Y₂ or Y₃ is O, SO₂, or         N—R₁₀,         -   wherein         -   R₁₀ is H, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, (C₁-C₄ alkyl)-CF₃,             (C₁-C₄ alkyl)-OCH₃, (C₁-C₄ alkyl)-halogen, SO₂—(C₁-C₄             alkyl), SO₂—(C₁-C₄ alkyl)-CF₃, SO₂—(C₁-C₄ alkyl)-OCH₃,             SO₂—(C₁-C₄ alkyl)-halogen, C(O)—(C₁-C₄ alkyl), C(O)—(C₁-C₄             alkyl)-CF₃, C(O)—(C₁-C₄ alkyl)-OCH₃, C(O)—(C₁-C₄             alkyl)-halogen, C(O)—NH—(C₁-C₄ alkyl), C(O)—N(C₁-C₄ alkyl)₂,             C₁-C₄ alkyl)-C(O)OH, or oxetane.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1;     -   Y₁ and Y₄ are each CH₂; and     -   one of Y₂ or Y₃ is CH₂ and the other of Y₂ or Y₃ is O, SO₂, or         N—R₁₀,         -   wherein         -   R₁₀ is H, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, (C₁-C₄ alkyl)-CF₃,             (C₁-C₄ alkyl)-OCH₃, (C₁-C₄ alkyl)-halogen, SO₂—(C₁-C₄             alkyl), SO₂—(C₁-C₄ alkyl)-CF₃, SO₂—(C₁-C₄ alkyl)-OCH₃,             SO₂—(C₁-C₄ alkyl)-halogen, C(O)—(C₁-C₄ alkyl), C(O)—(C₁-C₄             alkyl)-CF₃, C(O)—(C₁-C₄ alkyl)-OCH₃, C(O)—(C₁-C₄             alkyl)-halogen, C(O)—NH—(C₁-C₄ alkyl), C(O)—N(C₁-C₄ alkyl)₂,             C₁-C₄ alkyl)-C(O)OH, or oxetane.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound

-   -   wherein R₁₀ is H, CH₃, CH₂CH₃, CH₂CH₂CH₃, CH(CH₃)₂, CH₂CH(CH₃)₂,         t-Bu, CH₂OCH₃, CH₂CF₃, CH₂Cl, CH₂F, CH₂CH₂OCH₃, CH₂CH₂CF₃,         CH₂CH₂Cl, CH₂CH₂F, or

In some embodiments, the compound

-   -   wherein R₁₀ is SO₂—CH₃, SO₂—CH₂CH₃, SO₂—CH₂CH₂CH₃, SO₂—CH(CH₃)₂,         SO₂—CH₂CH(CH₃)₂, SO₂-t-Bu, SO₂—CH₂OCH₃, SO₂—CH₂CF₃, SO₂—CH₂Cl,         SO₂—CH₂F, SO₂—CH₂CH₂OCH₃, SO₂—CH₂CH₂CF₃, SO₂—CH₂CH₂Cl,         SO₂—CH₂CH₂F, or

In some embodiments, the compound

-   -   wherein R₁₀ is C(O)—CH₃, C(O)—CH₂CH₃, C(O)—CH₂CH₂CH₃,         C(O)—CH(CH₃)₂, C(O)—CH₂CH(CH₃)₂, C(O)-t-Bu, C(O)—CH₂OCH₃,         C(O)—CH₂CF₃, C(O)—CH₂Cl, C(O)—CH₂F, C(O)—CH₂CH₂OCH₃,         C(O)—CH₂CH₂CF₃, C(O)—CH₂CH₂Cl, C(O)—CH₂CH₂F,

In some embodiments, the compound

-   -   wherein     -   β, δ, ϵ, and φ are present;     -   α and χ are absent;     -   Z₁ is N;     -   Z₂ is O or N—R₇,         -   wherein R₇ is H, C₁-C₄ alkyl, or oxetane; and     -   X is C.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   R₇ is H, C₁-C₄ alkyl, or oxetane; and     -   Y₁, Y₂, Y₃ and Y₄ are each independently CR₈ or N,         -   wherein each R₈ is independently H, halogen, C₁-C₄ alkyl,             C₁-C₄ cycloalkyl, O—(C₁-C₄ alkyl), C(O)OH, C(O)—NH₂,             C(O)—N(CH₃)₂, C(O)—NHCH₃, NHC(O)—N(CH₃)₂, CN, or CF₃.

In some embodiments, the compound

-   -   wherein     -   Y₁, Y₂, Y₃ and Y₄ are each CH;     -   Y₁, Y₃, Y₃ are each CH and Y₄ is N;     -   Y₁, Y₂, Y₄ are each CH and Y₃ is N;     -   Y₁, Y₃, Y₄ are each CH and Y₂ is N; or     -   Y₂, Y₃, Y₄ are each CH and Y₁ is N.

In some embodiments, the compound B has the structure:

In some embodiments, the compound B has the structure:

In some embodiments, the compound

-   -   wherein     -   R₇ is H, CH₂CH₃, CH₃, CH(CH₃)₂, or

and

-   -   each R₈ is independently H, Cl, Br, F, OCH₃, OCH₂CH₃, CF₃, CN,         CH₃, CH₃CH₃, C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃, or         NHC(O)—N(CH₃)₂.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   Y₁, Y₂, Y₃ and Y₄ are each independently CR₈ or N,         -   wherein R₈ is H, halogen, C₁-C₄ alkyl, C₁-C₄ cycloalkyl,             O—(C₁-C₄ alkyl), C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃,             NHC(O)—N(CH₃)₂, CN, or CF₃,

In some embodiments, the compound

-   -   wherein     -   Y₁, Y₂, Y₃ and Y₄ are each CH;     -   Y₁, Y₂, Y₃ are each CH and Y₄ is N;     -   Y₁, Y₂, Y₄ are each CH and Y₃ is N;     -   Y₁, Y₃, Y₄ are each CH and Y₂ is N; or     -   Y₂, Y₃, Y₄ are each CH and Y₁ is N.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound

-   -   wherein     -   α and β are present;     -   χ, δ, ϵ, and φ are absent;     -   Z₁ is N;     -   Z₂ is N; and     -   X is N.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1;     -   Y₁ and Y₄ are each CH₂; and     -   one of Y₂ or Y₃ is CH₂ and the other of Y₂ or Y₃ is O, SO₂, or         N—R₁₀,         -   wherein         -   R₁₀ is H, C₁-C₄ alkyl, C1-C4 cycloalkyl, (C₁-C₄ alkyl)-CF₃,             (C₁-C₄ alkyl)-OCH₃, (C₁-C₄ alkyl)-halogen, SO₂—(C₁-C₄             alkyl), SO₂—(C₁-C₄ alkyl)-CF₃, SO₂—(C₁-C₄ alkyl)-OCH₃,             SO₂—(C₁-C₄ alkyl)-halogen, C(O)—(C₁-C₄ alkyl), C(O)—(C₁-C₄             alkyl)-CF₃, C(O)—(C₁-C₄ alkyl)-OCH₃, C(O)—(C₁-C₄             alkyl)—halogen, C(O)—NH—(C₁-C₄ alkyl), C(O)—N(C₁-C₄ alkyl)₂,             (C₁-C₄ alkyl)-C(O)OH, or oxetane.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound

-   -   wherein R₁₀ is H, CH₃, CH₂CH₃, CH₂CH₂CH₃, CH(CH₃)₂, CH₂CH(CH₃)₂,         t-Bu, CH₂OCH₃, CH₂CF₃, CH₂Cl, CH₂F, CH₂CH₂OCH₃, CH₂CH₂CF₃,         CH₂CH₂Cl, CH₂CH₂F, or

In some embodiments, the compound

-   -   wherein R₁₀ is SO₂—CH₃, SO₂—CH₂CH₃, SO₂—CH₂CH₂CH₃, SO₃—CH(CH₃)₂,         SO₂—CH₂CH(CH₃)₂, SO₂-t-Bu, SO₂—CH₂OCH₃, SO₂—CH₂CF₃, SO₂—CH₂Cl,         SO₂—CH₂F, SO₂—CH₂CH₂OCH₃, SO₂—CH₂CH₂CF₃, SO₂—CH₂CH₂Cl,         SO₂—CH₂CH₂F, or

In some embodiments, the compound

-   -   wherein R₁₀ is C(O)—CH₃, C(O)—CH₂CH₃, C(O)—CH₂CH₂CH₃,         C(O)—CH(CH₃)₂, C(O)—CH₂CH(CH₃)₂, C(O)-t-Bu, C(O)—CH₂OCH₃,         C(O)—CH₂CF₃, C(O)—CH₂Cl, C(O)—CH₂F, C(O)—CH₂CH₂OCH₃,         C(O)—CH₂CH₂CF₃, C(O)—CH₂CH₂Cl, C(O)—CH₂CH₂F,

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound

-   -   wherein     -   α, β, ϵ, φ and are present;     -   χ and δ are absent;     -   Z₁ is N;     -   Z₂ is N; and     -   X is N.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   Y₁, Y₂, Y₃ and Y₄ are each independently CR₈ or N,         -   wherein each R₈ is independently H, halogen, C₁-C₄ alkyl,             C₁-C₄ cycloalkyl, O(C₁-C₄ alkyl), CN, CF₃, C(O)OH, C(O)—NH₂,             C(O)—N(CH₃)₂, C(O)—NHCH₃, or NHC(O)—N(CH₃)₂

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound

-   -   wherein each R₈ is independently H, Cl, Br, F, OCH₃, OCH₂CH₃,         CF₃, CN, CH₃, CH₃CH₃, C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂,         C(O)—NHCH₃, NHC(O)—NHCH₃, NBC(O)—N(CH₃)₂, SO₂—NHCH₃ or         SO₂—N(CH₃)₂.

In some embodiments, the compound

-   -   wherein     -   α, χ, ϵ, and φ are present;     -   β and δ are absent;     -   Z₁ is O or S;     -   Z₂ is N; and     -   X is C.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   Y₁, Y₂, Y₃ and Y₄ are each independently CR₈ or N,         -   wherein each R₈ is independently H, halogen, O—(C₁-C₄             alkyl), CN, or CF₃.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein B has the structure:

wherein α, β, χ, and δ are each independently absent or present, and when present each is a bond; X is C or N; Z₃ is CH, S, O, N or NR₁₁,

-   -   wherein R₁₁ is H or C₁-C₁₀ alkyl;         Z₄ is CH, S, O, N or NR₁₂,     -   wherein R₁₂ is H or C₁-C₁₀ alkyl;         Q is a substituted or unsubstituted 5, 6, or 7 membered ring         structure.

In some embodiments of the above compound, the compound wherein when α is present, then Z₃ are N, Z₄ is CH, X is N, β and δ are absent, and χ is present;

when α is absent, then Z₃ is CH or N, Z₄ is NH₇, S, or O, X is C, β and δ are present, and χ is absent.

In some embodiments, the compound wherein B has the structure:

wherein n is an integer from 0-2; α, β, χ, δ, ϵ, and φ are each independently absent or present, and when present each is a bond; X is C or N; Z₃ is CH, S, O, N or NR₁₁,

-   -   wherein R₁₁ is H or C₁-C₁₀ alkyl;         Z₄ is CH, S, O, N or NR₁₂,     -   wherein R₁₂ is H or C₁-C₁₀ alkyl;         Y₁, Y₂, Y₃, and each occurrence of Y₄ are each independently         CR₁₃, C(R₁₄)₂, N—R₁₅, O, N, SO₂, or C═O,     -   wherein     -   R₁₃ is H, halogen, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl, O—(C₁-C₁₀         alkyl), C(O)OH, C(O)O(C₁-C₁₀ alkyl), C(O)—NH₂, C(O)—NH(C₁-C₄         alkyl), C(O)—NH(C₁-C₄ alkyl)₂, NHC(O)—NH(C₁-C₁₀ alkyl),         NHC(O)—N(C₁-C₄ alkyl)₂, SO₂—NH(C₁-C₁₀ alkyl), SO₂—N(C₁-C₁₀         alkyl)₂, CN, CF₃, imidazole, morpholino, or pyrrolidine     -   R₁₄ is H or C₁-C₁₀ alkyl;     -   R₁₅ is H, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl, (C₁-C₁₀ alkyl)-CF₃,         (C₁-C₁₀ alkyl)-OCH₃, (C₁-C₁₀ alkyl)-halogen, SO₂—(C₁-C₁₀ alkyl),         SO₂—C₁-C₁₀ alkyl)-CF₃, SO₂—(C₁-C₁₀ alkyl)-OCH₃, SO₂—(C₁-C₁₀         alkyl)-halogen, C(O)—(C₁-C₁₀ alkyl), C(O)—(C₁-C₁₀ alkyl)-CF₃,         C(O)—(C₁-C₁₀ alkyl)-OCH₃, C(O)—(C₁-C₁₀ alkyl)-halogen,         C(O)—NH—(C₁-C₁₀ alkyl), C(O)—N(C₁-C₄ alkyl)₂, (C₁-C₁₀         alkyl)-C(O)OH, C(O)—NH₂ or oxetane.

In some embodiments of the above compound, the compound wherein

when α is present, then Z₃ are N, Z₄ is CH, X is N, β and δ are absent, and χ is present;

when α is absent, then Z₃ is CH or N, Z₄ is NR₁₂, S, or O, X is C, β and δ are present, and χ is absent;

when ϵ and φ are each present, then n=1, and each of Y₁, Y₂, Y₃, and Y₄ are independently C—R₁₃ or N;

when ϵ and φ are each absent, then n=0, 1 or 2, each of Y₁, Y₂, Y₃, and each occurrence of Y₄ are independently C(R₁₄)₂, N—R₁₅, O, or SO₂.

In some embodiments, the compound

-   -   wherein     -   α, χ, ϵ, and φ are each present, β and δ are each absent, Z₃ is         CH, Z₄ is N; and X is N; or     -   χ, δ, ϵ, and φ are each present, α and β are each absent, Z₃ is         CH, Z₄ is N—R₁₂; and X is C; or     -   χ, δ, ϵ, and φ are each present, α and β are each absent, Z₃ is         N, Z₄ is N—R₁₂, S or O; and X is C.

In some embodiments, the compound wherein 18 has the structure:

-   -   wherein     -   n is 1; and     -   Y₁, Y₂, Y₃, and Y₄ are each C—R₁₃ or N,         -   wherein R₁₃ is H, halogen, C₁-C₄ alkyl, C₁-C₄ cycloalkyl,             O—(C₁-C₄ alkyl), C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃,             NHC(O)—N(CH₃)₂, CN, CF₃, imidazole, morpholino, or             pyrrolidine.

In some embodiments, the compound wherein

-   -   Y₁, Y₂, Y₃, and Y₄ are each C—R₁₃; or     -   Y₁ is N, and Y₂, Y₃, and Y₄ are each C—R₁₃.

In some embodiments, the compound wherein B has the structure:

-   -   wherein is R₁₃ is H, halogen, C₁-C₄ alkyl, C₁-C₄ cycloalkyl,         O—(C₁-C₄ alkyl), C₁-C₄ cycloalkyl, C(O)OH, C(O)—NH₂,         C(O)—N(CH₃)₂, C(O)—NHCH₃, NHC(O)—N(CH₃)₂, CN, CF₃, imidazole,         morpholino, or pyrrolidine.

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1;     -   R₁₂ is H or C₁-C₄ alkyl;     -   Y₁, Y₂, Y₃, and Y₄ are each C—R₁₃ or N,         -   wherein R₁₃ is H, halogen, C₁-C₄ alkyl, C₁-C₄ cycloalkyl,             O—(C₁-C₄ alkyl), C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃,             NHC(O)—N(CH₃)₂, CN, CF₃, imidazole, morpholino, or             pyrrolidine.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein R₁₃ is H, CH₃, CF₃, OCH₃, F, Cl,

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   n is 1; and     -   Y₁, Y₂, Y₃ and Y₄ are each C—R₁₃ or N,         -   wherein R₁₃ is H, halogen, C₁-C₄ alkyl, C₁-C₁₀ cycloalkyl,             O—(C₁-C₄ alkyl), C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃,             NHC(O)—N(CH₃)₂, CN, CF₃, imidazole, morpholino, or             pyrrolidine.

In some embodiments, the compound

-   -   wherein     -   Y₁, Y₂, Y₃, and Y₄ are each C—R₁₃, or     -   one of Y₁, Y₂, Y₃, or Y₄ is N and the other three of Y₁, Y₂, Y₃,         or Y₄ are each C—R₁₃,         -   wherein each R₁₃ is H.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₁₆, R₁₇, and R₁₈ are each H, halogen, C₁-C₄ alkyl or         C₁-C₄ cycloalkyl.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein B is a substituted or unsubstituted monocycle or heteromonocycle.

In some embodiments, the compound wherein B is a substituted or unsubstituted imidazole, pyridazine, pyrazole, pyrazine, thiadiazole, or triazole.

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₁₉ is H, halogen CN, CF₃, OH, NH₂, C₁-C₄ alkyl, C₃-C₆         cycloalkyl, O(C₁-C₄ alkyl), C(O)NH₂, C(O)NH(C₁-C₄ alkyl),         C(O)N(C₁-C₄ alkyl)₂, C(O)OH, C(O)O(C₁-C₄ alkyl), C(O)(C₁-C₄         alkyl), C(O)NH(SO₂)—(C₁-C₄ alkyl), C(O)NH(SO₂)—(C₁-C₆         cycloalkyl), C(O)NH(SO₂)-(aryl), O(SO₂)—NH₂, NHC(O)—NH(C₁-C₄         alkyl), NHC(O)—N(C₁-C₄ alkyl)₂, SO₂—(C₁-C₄ alkyl) or tetrazole.

In some embodiments, the compound wherein R₁₉ is H, Cl, Br, F, OCH₃, OCH₂CH₃, CF₃, CN, CH₃, CH₃CH₃, COOH, or COOCH₃.

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein B has the structure:

-   -   wherein     -   R₂₀ is H, halogen, C₁-C₄ alkyl, C₃-C₆ cycloalkyl, O—(C₁-C₄         alkyl), C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃,         NHC(O)—N(CH₃)₂, CN or CF₃.

In some embodiments, the compound wherein

-   -   R₂₀ is H, CH₃, or CH₂CH₃; and     -   R₂₁ is H, Cl, Br, F, OCH₃, OCH₂CH₃, CF₃, CN, CH₃, or CH₃CH₃.

In some embodiments, the compound wherein B is a substituted or unsubstituted phenyl, pyridine, pyrimidine, benzyl, pyrrolidine, sulfolane, oxetane, CO₂H or (C₁-C₄ alkyl)-CO₂H; or

B is

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₁, R₂₂, R₂₃, R₂₄, and R₂₅ are each independently H,         halogen CN, CF₃, OH, NH₂, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl,         O(C₁-C₄ alkyl), C(O)NH₂, C(O)NH(C₁-C₄ alkyl), C(O)N(C₁-C₄         alkyl)₂, C(O)OH, C(O)O(C₁-C10 alkyl), C(O)(C₁-C₄ alkyl),         C(O)NH(SO₂)—(C₁-C₄ alkyl), C(O)NH(SO₂)—(C₃-C₆ cycloalkyl),         C(O)NH(SO₂)-(aryl), O(SO₂)—NH₂, NHC(O)—NH(C₁-C₄ alkyl),         NHC(O)—N(C₁-C₄ alkyl)₂, SO₂—(C₁-C₁₀ alkyl) or tetrazole.

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₁, R₂₂, and R₂₃ are each independently     -   H, halogen, OH, CF₃, NH₂, C₁-C₄ alkyl, C₃-C₆ cycloalkyl, O(C₁-C₄         alkyl), C(O)NH₂, C(O)NH(C₁-C₄ alkyl), C(O)N(C₁-C₄ alkyl)₂,         C(O)OH, C(O)O(C₁-C₄ alkyl), C(O)(C₁-C₄ alkyl),         C(O)NH(SO₂)—(C₁-C₄ alkyl), C(O)NH(SO₂)—(C₃-C₆ cycloalkyl),         C(O)NH(SO₂)-(aryl), or O(SO₂)—NH₂, SO₂—(C₁-C₄ alkyl).

In some embodiments, the compound wherein R₂₁, R₂₂, and R₂₃ are each independently F, Cl, CH₃, CF₃, OCH₃, OH, SO₂—CH₃, C(O)NH₂, C(O)OH, C(O)OCH₃,

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₂, R₂₃, R₂₄ and R₂₅ are each independently     -   H, halogen, OH, CF₃, NH₂, C₁-C₄ alkyl, C₃-C₆ cycloalkyl, O(C₁-C₄         alkyl), C(O)NH₂, C(O)NH(C₁-C₄ alkyl), C(O)N(C₁-C₄ alkyl)₂,         C(O)OH, C(O)O(C₁-C₄ alkyl), C(O)(C₁-C₄ alkyl),         C(O)NH(SO₂)—(C₁-C₄ alkyl), C(O)NH(SO₂)—(C₁-C₆ cycloalkyl),         C(O)NH(SO₂)-(aryl), O(SO₂)—NH₂, or SO₂—(C₁-C₄ alkyl).

In some embodiments, the compound wherein R₂₂, R₂₃, R₂₄ and R₂₅ are each independently H, F, Cl, CF₃, CH₃, OCH₃, OH, SO₂—CH₃, C(O)NH₂, C(O)OH, C(O)OCH₃,

In some embodiments, the compound wherein R₂₂, R₂₄, R₂₅, are each H and R₂₃ in F, Cl, CH₃, CF₃, OCH₃, OH, SO₂—CH₃, C(O)NH₂, C(O)OH, C(O)OCH₃,

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₁, R₂₂, R₂₃, R₂₄, and R₂₅ are each independently     -   H, halogen CN, CF₃, OH, NH₂, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl,         O(C₁-C₁₀ alkyl), C(O)NH₂, C(O)NH(C₁-C₁₀ alkyl), C(O)N(C₁-C₄         alkyl)₂, C(O)OH, C(O)O(C₁-C₁₀ alkyl), C(O)(C₁-C₁₀ alkyl),         C(O)NH(SO₂)—(C₁-C₁₀ alkyl), C(O)NH(SO₂)—(C₃-C₆ cycloalkyl),         C(O)NH(SO₂)-(aryl), O(SO₂)—NH₂, NHC(O)—NH(C₁-C₁₀ alkyl),         NHC(O)—N(C₁-C₄ alkyl)₂, SO₂—(C₁-C₁₀ alkyl).

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₁ and R₂₅ are each independently     -   H, halogen, OH, NH₂, C₁-C₄ alkyl, C₃-C₆ cycloalkyl, O(C₁-C₄         alkyl), C(O)NH₂, C(O)NH(C₁-C₄ alkyl), C(O)N(C₁-C₄ alkyl)₂,         C(O)OH, C(O)O(C₁-C₄ alkyl), C(O)(C₁-C₄ alkyl),         C(O)NH(SO₂)—(C₁-C₄ alkyl), C(O)NH(SO₂)—(C₃-C₆ cycloalkyl),         C(O)NH(SO₂)-(aryl), or O(SO₂)—NH₂, SO₂—(C₁-C₄ alkyl).

In some embodiments, the compound wherein R₂₁ and R₂₅ are each independently F, Cl, CF₃, CH₃, OCH₃, OH, SO₂—CH₃, C(O)NH₂, C(O)OH, C(O)OCH₃,

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₂, R₂₃, R₂₄ and R₂₃ are each independently     -   H, halogen, OH, NH₂, C₁-C₄, alkyl, C₃-C₆ cycloalkyl, O(C₁-C₄         alkyl), C(O)NH₂, C(O)NH(C₁-C₄ alkyl), C(O)N(C₁-C₄ alkyl)₂,         C(O)OH, C(O)O(C₁-C₄ alkyl), C(O)(C₁-C₄ alkyl),         C(O)NH(SO₂)—(C₁-C₄ alkyl), C(O)NH(SO₂)—(C₃-C₆ cycloalkyl),         C(O)NH(SO₂)-(aryl), or O(SO₂)—NH₂, SO₂—(C₁-C₄ alkyl).

In some embodiments, the compound wherein R₂₁, R₂₂, R₂₃, R₂₄ and R₂₅ are each independently H, F, Cl, CF₃, CH₃, OCH₃, OH, SO₂—CH₃, C(O)NH₂, C(O)OH, C(O)OCH₃,

In some embodiments, the compound wherein R₂₂, R₂₄, R₂₅ are each H and R₂₃ is F, Cl, CF₃, CH₃, OCH₃, OH, SO₂—CH₃, C(O)NH₂, C(O)OH, C(O)OCH₃,

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₁, R₂₂, R₂₃, R₂₄, and R₂₅ are each independently     -   H, halogen CN, CF₃, OH, NH₂, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl,         O(C₁-C₁₀ alkyl), C(O)NH₂, C(O)NH(C₁-C₁₀ alkyl), C(O)N(C₁-C₄         alkyl)₂, C(O)OH, C(O)O(C₁-C₁₀ alkyl), C(O)(C₁-C₁₀ alkyl),         C(O)NH(SO₂)—(C₁-C₁₀ alkyl), C(O)NH(SO₂)—(C₃-C₆ cycloalkyl),         C(O)NH(SO₂)-(aryl), O(SO₂)—NH₂, NHC(O)—NH(C₁-C₁₀ alkyl),         NHC(O)—N(C₁-C₄ alkyl)₂, SO₂—(C₁-C₁₀ alkyl).

In some embodiments, the compound wherein B has the structure:

-   -   wherein R₂₁, R₂₂, R₂₄ and R₂₅ are each independently     -   H, halogen, OH, NH₂, alkyl, C₃-C₆ cycloalkyl, O(C₁-C₄ alkyl),         C(O)NH₂, C(O)NH(C₁-C₄ alkyl), C(O)N(C₁-C₄ alkyl)₂, C(O)OH,         C(O)O(C₁-C₄ alkyl), C(O)(C₁-C₄ alkyl), C(O)NH(SO₂)—(C₁-C₄         alkyl), C(O)NH(SO₂)—(C₃-C₆ cycloalkyl), C(O)NH(SO₂)-(aryl), or         O(SO₂)—NH₂, SO₂—(C₁-C₄ alkyl).

In some embodiments, the compound wherein R₂₁, R₂₂, R₂₄ and R₂₅ are each independently H, F, Cl, CF₃, CH₃, OCH₃, OH, SO₂—CH₃, C(O)NH₂, C(O)OH, C(O)OCH₃,

In some embodiments, the compound wherein B has the structure

In some embodiments, the compound wherein B has the structure:

In some embodiments, the compound wherein R₆ is C₁-C₄ alkyl.

In some embodiments, the compound wherein R₆ is CH₃.

In some embodiments, the compound wherein

-   -   R₁, R₂, R₃, R₄, and R₅ are each H, t-Bu, Cl, F, or CF₃; and     -   R₆ is C₁-C₄ alkyl.

In some embodiments, the compound wherein

-   -   R₁, R₂, R₃ and R₄ are each H,     -   R₅ is CF₃; and     -   R₆ is CH₃.

In some embodiments, the compound wherein

-   -   R₁, R₂, R₃, and R₄ are each H,     -   R₅ is t-Hu or i-Pr; and     -   R₆ is CH₃.

In some embodiments, the compound wherein

-   -   R₁, R₃, and R₅ are each H,     -   R₂ and R₄ is CF₃; and     -   R₆ is CH₃.

In some embodiments, the compound having the structure:

The present invention provides a pharmaceutical composition comprising a compound of the present invention and a pharmaceutically acceptable carrier.

The present invention provides a method for treating a disease characterized by excessive lipofuscin accumulation in the retina in a mammal afflicted therewith comprising administering to the mammal an effective amount of a compound of the present invention or a composition of the present invention.

In some embodiments of the method, wherein the disease is further characterized by bisretinoid-mediated macular degeneration.

In some embodiments of the method, wherein the amount of the compound is effective to lower the serum concentration of RBP4 in the mammal.

In some embodiments of the method, wherein the amount of the compound is effective to lower the retinal concentration of a bisretinoid in lipofuscin in the mammal.

In some embodiments of the method, wherein the bisretinoid is A2E. In some embodiments of the method, wherein the bisretinoid is isoA2E. In some embodiments of the method, wherein the bisretinoid is A2-DHP-PE. In some embodiments of the method, wherein the bisretinoid is atRAL di-PE.

In some embodiments of the method, wherein the disease characterized by excessive lipofuscin accumulation in the retina is Age-Related Macular Degeneration.

In some embodiments of the method, wherein the disease characterized by excessive lipofuscin accumulation in the retina is dry (atrophic) Age-Related Macular Degeneration.

In some embodiments of the method, wherein the disease characterized by excessive lipofuscin accumulation in the retina is Stargardt Disease.

In some embodiments of the method, wherein the disease characterized by excessive lipofuscin accumulation in the retina is Best disease.

In some embodiments of the method, wherein the disease characterized by excessive lipofuscin accumulation in the retina is adult vitelliform maculopathy.

In some embodiments of the method, wherein the disease characterized by excessive lipofuscin accumulation in the retina is Stargardt-like macular dystrophy.

In some embodiments, B has the structure:

In some embodiments, bisretinoid-mediated macular degeneration is Age-Related Macular Degeneration or Stargardt Disease.

In some embodiments, the bisretinoid-mediated macular degeneration is Age-Related Macular Degeneration.

In some embodiments, the bisretinoid-mediated macular degeneration is dry (atrophic) Age-Related Macular Degeneration.

In some embodiments, the bisretinoid-mediated macular degeneration is Stargardt Disease.

In some embodiments, the bisretinoid-mediated macular degeneration is Best disease.

In some embodiments, the bisretinoid-mediated macular degeneration is adult vitelliform maculopathy.

In some embodiments, the bisretinoid-mediated macular degeneration is Stargardt-like macular dystrophy.

The bisretinoid-mediated macular degeneration may comprise the accumulation of lipofuscin deposits in the retinal pigment epithelium.

As used herein, “bisretinoid lipofuscin” is lipofuscin containing a cytotoxic bisretinoid. Cytotoxic bisretinoids include but are not necessarily limited to A2E, isoA2E, atRAL di-PE, and A2-DHP-PE (FIGS. 1, 2, and 3).

Except where otherwise specified, when the structure of a compound of this invention includes an asymmetric carbon atom, it is understood that the compound occurs as a racemate, racemic mixture, and isolated single enantiomer. All such isomeric forms of these compounds are expressly included in this invention. Except where otherwise specified, each stereogenic carbon may be of the R or S configuration. It is to be understood accordingly that the isomers arising from such asymmetry (e.g., all enantiomers and diastereomers) are included within the scope of this invention, unless indicated otherwise. Such isomers can be obtained in substantially pure form by classical separation techniques and by stereochemically controlled synthesis, such as those described in “Enantiomers, Racemates and Resolutions” by J. Jacques, A. Collet and S. Wilen, Pub. John Wiley & Sons, NY, 1981. For example, the resolution may be carried out by preparative chromatography on a chiral column.

The subject invention is also intended to include all isotopes of atoms occurring on the compounds disclosed herein. Isotopes include those atoms having the same atomic number but different mass numbers. By way of general example and without limitation, isotopes of hydrogen include tritium and deuterium. Isotopes of carbon include C-13 and C-14.

It will be noted that any notation of a carbon in structures throughout this application, when used without further notation, are intended to represent all isotopes of carbon, such as ¹²C, ¹³C, or ¹⁴C. Furthermore, any compounds containing ¹³C or ¹⁴C may specifically have the structure of any of the compounds disclosed herein.

It will also be noted that any notation of a hydrogen in structures throughout this application, when used without further notation, are intended to represent all isotopes of hydrogen, such as ¹H, ²H, or ³H. Furthermore, any compounds containing ²H or ³H may specifically have the structure of any of the compounds disclosed herein.

Isotopically-labeled compounds can generally be prepared by conventional techniques known to those skilled in the art using appropriate isotopically-labeled reagents in place of the non-labeled reagents employed.

The term “substitution”, “substituted” and “substituent” refers to a functional group as described above in which one or more bonds to a hydrogen atom contained therein are replaced by a bond to non-hydrogen or non-carbon atoms, provided that normal valencies are maintained and that the substitution results in a stable compound. Substituted groups also include groups in which one or more bonds to a carbon(s) or hydrogen(s) atom are replaced by one or more bonds, including double or triple bonds, to a heteroatom. Examples of substituent groups include the functional groups described above, and halogens (i.e., F, Cl, Br, and I); alkyl groups, such as methyl, ethyl, n-propyl, isopropryl, n-butyl, tert-butyl, and trifluoromethyl; hydroxyl; alkoxy groups, such as methoxy, ethoxy, n-propoxy, and isopropoxy; aryloxy groups, such as phenoxy; arylalkyloxy, such as benzyloxy (phenylmethoxy) and p-trifluoromethylbenzyloxy(4-trifluoromethylphenylmethoxy); heteroaryloxy groups; sulfonyl groups, such as trifluoromethanesulfonyl, methanesulfonyl, and p-toluenesulfonyl; nitro, nitrosyl; mercapto; sulfanyl groups, such as methylsulfanyl, ethylsulfanyl and propylsulfanyl; cyano; amino groups, such as amino, methylamino, dimethylamino, ethylamino, and diethylamino; and carboxyl. Where multiple substituent moieties are disclosed or claimed, the substituted compound can be independently substituted by one or more of the disclosed or claimed substituent moieties, singly or plurally. By independently substituted, it is meant that the (two or more) substituents can be the same or different.

In the compounds used in the method of the present invention, the substituents may be substituted or unsubstituted, unless specifically defined otherwise.

In the compounds used in the method of the present invention, alkyl, heteroalkyl, monocycle, bicycle, aryl, heteroaryl and heterocycle groups can be further substituted by replacing one or more hydrogen atoms with alternative non-hydrogen groups. These include, but are not limited to, halo, hydroxy, mercapto, amino, carboxy, cyano and carbamoyl.

It is understood that substituents and substitution patterns on the compounds used in the method of the present invention can be selected by one of ordinary skill in the art to provide compounds that are chemically stable and that can be readily synthesized by techniques known in the art from readily available starting materials. If a substituent is itself substituted with more than one group, it is understood that these multiple groups may be on the same carbon or on different carbons, so long as a stable structure results.

In choosing the compounds used in the method of the present invention, one of ordinary skill in the art will recognize that the various substituents, i.e. R₁, R₂, etc. are to be chosen in conformity with well-known principles of chemical structure connectivity.

As used herein, “alkyl” includes both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms and may be unsubstituted or substituted. Thus, C₁-C_(n) as in “C₁-C_(n) alkyl” is defined to include groups having 1, 2, . . . , n−1 or n carbons in a linear or branched arrangement. For example, C₁-C₆, as in “C₁-C₆ alkyl” is defined to include groups having 1, 2, 3, 4, 5, or 6 carbons in a linear or branched arrangement, and specifically includes methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, pentyl, and hexyl. Unless otherwise specified contains one to ten carbons. Alkyl groups can be unsubstituted or substituted with one or more substituents, including but not limited to halogen, alkoxy, alkylthio, trifluoromethyl, difluoromethyl, methoxy, and hydroxyl.

As used herein, “C₁-C₄ alkyl” includes both branched and straight-chain C₁-C₄ alkyl.

As used herein, “alkenyl” refers to a non-aromatic hydrocarbon radical, straight or branched, containing at least 1 carbon to carbon double bond, and up to the maximum possible number of non-aromatic carbon-carbon double bonds may be present, and may be unsubstituted or substituted. For example, “C₂-C₆ alkenyl” means an alkenyl radical having 2, 3, 4, 5, or 6 carbon atoms, and up to 1, 2, 3, 4, or 5 carbon-carbon double bonds respectively. Alkenyl groups include ethenyl, propenyl, butenyl and cyclohexenyl.

As used herein, “heteroalkyl” includes both branched and straight-chain saturated aliphatic hydrocarbon groups having at least 1 heteroatom within the chain or branch.

As used herein, “cycloalkyl” includes cyclic rings of alkanes of three to eight total carbon atoms, or any number within this range (i.e., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl).

As used herein, “heterocycloalkyl” is intended to mean a 5- to 10-membered nonaromatic ring containing from 1 to 4 heteroatoms selected from the group consisting of O, N and S, and includes bicyclic groups. “Heterocyclyl” therefore includes, but is not limited to the following: imidazolyl, piperazinyl, piperidinyl, pyrrolidinyl, morpholinyl, thiomorpholinyl, tetrahydropyranyl, dihydropiperidinyl, tetrahydrothiophenyl and the like. If the heterocycle contains nitrogen, it is understood that the corresponding N-oxides thereof are also encompassed by this definition.

As used herein, “aryl” is intended to mean any stable monocyclic, bicyclic or polycyclic carbon ring of up to 10 atoms in each ring, wherein at least one ring is aromatic, and may be unsubstituted or substituted. Examples of such aryl elements include but are not limited to: phenyl, p-toluenyl (4-methylphenyl), naphthyl, tetrahydro-naphthyl, indanyl, phenanthryl, anthryl or acenaphthyl. In cases where the aryl substituent is bicyclic and one ring is non-aromatic, it is understood that attachment is via the aromatic ring.

The term “alkylaryl” refers to alkyl groups as described above wherein one or more bonds to hydrogen contained therein are replaced by a bond to an aryl group as described above. It is understood that an “alkylaryl” group is connected to a core molecule through a bond from the alkyl group and that the aryl group acts as a substituent on the alkyl group. Examples of arylalkyl moieties include, but are not limited to, benzyl (phenylmethyl), p-trifluoromethylbenzyl(4-trifluoromethylphenylmethyl), 1-phenylethyl, 2-phenylethyl, 3-phenylpropyl, 2-phenylpropyl and the like.

The term “heteroaryl” as used herein, represents a stable monocyclic, bicyclic or polycyclic ring of up to 10 atoms in each ring, wherein at least one ring is aromatic and contains from 1 to 4 heteroatoms selected from the group consisting of O, N and S. Bicyclic aromatic heteroaryl groups include but are not limited to phenyl, pyridine, pyrimidine or pyridizine rings that are (a) fused to a 6-membered aromatic (unsaturated) heterocyclic ring having one nitrogen atom; (b) fused to a 5- or 6-membered aromatic (unsaturated) heterocyclic ring having two nitrogen atoms; (c) fused to a 5-membered aromatic (unsaturated) heterocyclic ring having one nitrogen atom together with either one oxygen or one sulfur atom; or (d) fused to a 5-membered aromatic (unsaturated) heterocyclic ring having one heteroatom selected from O, N or S. Heteroaryl groups within the scope of this definition include but are not limited to: benzoimidazolyl, benzofuranyl, benzofurazanyl, benzopyrazolyl, benzotriazolyl, benzothiophenyl, benzoxazolyl, carbazolyl, carbolinyl, cinnolinyl, furanyl, indolinyl, indolyl, indolazinyl, indazolyl, isobenzofuranyl, isoindolyl, isoquinolyl, isothiazolyl, isoxazolyl, naphthpyridinyl, oxadiazolyl, oxazolyl, oxazoline, isoxazoline, oxetanyl, pyranyl, pyrazinyl, pyrazolyl, pyridazinyl, pyridopyridinyl, pyridazinyl, pyridyl, pyrimidyl, pyrrolyl, quinazolinyl, quinolyl, quinoxalinyl, tetrazolyl, tetrazolopyridyl, thiadiazolyl, thiazolyl, thienyl, triazolyl, azetidinyl, aziridinyl, 1,4-dioxanyl, hexahydroazepinyl, dihydrobenzoimidazolyl, dihydrobenzofuranyl, dihydrobenzothiophenyl, dihydrobenzoxazolyl, dihydrofuranyl, dihydroimidazolyl, dihydroindolyl, dihydroisooxazolyl, dihydroisothiazolyl, dihydrooxadiazolyl, dihydrooxazolyl, dihydropyrazinyl, dihydropyrazolyl, dihydropyridinyl, dihydropyrimidinyl, dihydropyrrolyl, dihydroquinolinyl, dihydrotetrazolyl, dihydrothiadiazolyl, dihydrothiazolyl, dihydrothienyl, dihydrotriazolyl, dihydroazetidinyl, methylenedioxybenzoyl, tetrahydrofuranyl, tetrahydrothienyl, acridinyl, carbazolyl, cinnolinyl, quinoxalinyl, pyrrazolyl, indolyl, benzotriazolyl, benzothiazolyl, benzoxazolyl, isoxazolyl, isothiazolyl, furanyl, thienyl, benzothienyl, benzofuranyl, quinolinyl, isoquinolinyl, oxazolyl, isoxazolyl, indolyl, pyrazinyl, pyridazinyl, pyridinyl, pyrimidinyl, pyrrolyl, tetra-hydroquinoline. In cases where the heteroaryl substituent is bicyclic and one ring is non-aromatic or contains no heteroatoms, it is understood that attachment is via the aromatic ring or via the heteroatom containing ring, respectively. If the heteroaryl contains nitrogen atoms, it is understood that the corresponding N-oxides thereof are also encompassed by this definition.

As used herein, “monocycle” includes any stable polycyclic carbon ring of up to 10 atoms and may be unsubstituted or substituted. Examples of such non-aromatic monocycle elements include but are not limited to: cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl. Examples of such aromatic monocycle elements include but are not limited to: phenyl. As used herein, “heteromonocycle” includes any monocycle containing at least one heteroatom.

As used herein, “bicycle” includes any stable polycyclic carbon ring of up to 10 atoms that is fused to a polycyclic carbon ring of up to 10 atoms with each ring being independently unsubstituted or substituted. Examples of such non-aromatic bicycle elements include but are not limited to: decahydronaphthalene. Examples of such aromatic bicycle elements include but are not limited to: naphthalene. As used herein, “heterobicycle” includes any bicycle containing at least one heteroatom.

The term “phenyl” is intended to mean an aromatic six membered ring containing six carbons, and any substituted derivative thereof.

The term “benzyl” is intended to mean a methylene attached directly to a benzene ring. A benzyl group is a methyl group wherein a hydrogen is replaced with a phenyl group, and any substituted derivative thereof.

The term “pyridine” is intended to mean a heteroaryl having a six-membered ring containing 5 carbon atoms and 1 nitrogen atom, and any substituted derivative thereof.

The term “pyrimidine” is intended to mean a heteroaryl having a six-membered ring containing 4 carbon atoms and 2 nitrogen atoms wherein the two nitrogen atoms are separated by one carbon atom, and any substituted derivative thereof.

The term “pyridazine” is intended to mean a heteroaryl having a six-membered ring containing 4 carbon atoms and 2 nitrogen atoms wherein the two nitrogen atoms are adjacent to each other, and any substituted derivative thereof.

The term “pyrazine” is intended to mean a heteroaryl having a six-membered ring containing 4 carbon atoms and 2 nitrogen atoms wherein the two nitrogen atoms are separated by two carbon atoms, and any substituted derivative thereof.

The term “pyrrolidine” is intended to mean a non-aromatic five-membered ring containing four carbon atoms and one nitrogen atom, and any substituted derivative thereof.

The term “triazole” is intended to mean a heteroaryl having a five-membered ring containing two carbon atoms and three nitrogen atoms, and any substituted derivative thereof.

The term “imidazole” is intended to mean a heteroaryl having a five-membered ring containing three carbon atoms and two nitrogen atoms, and any substituted derivative thereof.

The term “thiadiazole” is intended to mean a heteroaryl having a five-membered ring containing two carbon atoms, two nitrogen atoms, and one sulfur atom and any substituted derivative thereof.

The term “pyrazole” is intended to mean a heteroaryl having a five-membered ring containing three carbon atoms and two nitrogen atoms wherein the nitrogen atoms are adjacent to each other, and any substituted derivative thereof.

The term “triazine” is intended to mean a heteroaryl having a six-membered ring containing 3 carbon atoms and 3 nitrogen atoms, and any substituted derivative thereof.

The term “indole” is intended to mean a heteroaryl having a five-membered ring fused to a phenyl ring with the five-membered ring containing 1 nitrogen atom directly attached to the phenyl ring.

The term “benzimidazole” is intended to mean a heteroaryl having a five-membered ring fused to a phenyl ring with the five-membered ring containing 2 nitrogen atoms directly attached to the phenyl ring.

The term “oxatane” is intended to mean a non-aromatic four-membered ring containing three carbon atoms and one oxygen atom, and any substituted derivative thereof.

The term “sulfolane” is intended to mean a non-aromatic five-membered ring containing four carbon atoms and one sulfur atom wherein the sulfur atom is doubly bonded to two oxygen atoms and any substituted derivative thereof.

The compounds used in the method of the present invention may be prepared by techniques well know in organic synthesis and familiar to a practitioner ordinarily skilled in the art. However, these may not be the only means by which to synthesize or obtain the desired compounds.

The compounds of present invention may be prepared by techniques described in Vogel's Textbook of Practical Organic Chemistry, A. I. Vogel, A. R. Tatchell, B. S. Furnis, A. J. Hannaford, P. W. G. Smith, (Prentice Hall) 5^(th) Edition (1996), March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, Michael B. Smith, Jerry March, (Wiley-Interscience) 5^(th) Edition (2007), and references therein, which are incorporated by reference herein. However, these may not be the only means by which to synthesize or obtain the desired compounds.

The compounds of present invention may be prepared by techniques described herein. The synthetic methods used to prepare Examples 1-46 maybe used to prepare additional octahydrocyclopentapyrroles compounds which described herein.

The various R groups attached to the aromatic rings of the compounds disclosed herein may be added to the rings by standard procedures, for example those set forth in Advanced Organic Chemistry: Part B: Reaction and Synthesis, Francis Carey and Richard Sundberg, (Springer) 5th ed. Edition. (2007), the content of which is hereby incorporated by reference.

Another aspect of the invention comprises a compound of the present invention as a pharmaceutical composition.

As used herein, the term “pharmaceutically active agent” means any substance or compound suitable for administration to a subject and furnishes biological activity or other direct effect in the treatment, cure, mitigation, diagnosis, or prevention of disease, or affects the structure or any function of the subject. Pharmaceutically active agents include, but are not limited to, substances and compounds described in the Physicians' Desk Reference (PDR Network, LLC; 64th edition; Nov. 15, 2009) and “Approved Drug Products with Therapeutic Equivalence Evaluations” (U.S. Department Of Health And Human Services, 30^(th) edition, 2010), which are hereby incorporated by reference. Pharmaceutically active agents which have pendant carboxylic acid groups may be modified in accordance with the present invention using standard esterification reactions and methods readily available and known to those having ordinary skill in the art of chemical synthesis. Where a pharmaceutically active agent does not possess a carboxylic acid group, the ordinarily skilled artisan will be able to design and incorporate a carboxylic acid group into the pharmaceutically active agent where esterification may subsequently be carried out so long as the modification does not interfere with the pharmaceutically active agent's biological activity or effect.

The compounds of the present invention may be in a salt form. As used herein, a “salt” is a salt of the instant compounds which has been modified by making acid or base salts of the compounds. In the case of compounds used to treat a disease, the salt is pharmaceutically acceptable. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as phenols. The salts can be made using an organic or inorganic acid. Such acid salts are chlorides, bromides, sulfates, nitrates, phosphates, sulfonates, formates, tartrates, maleates, malates, citrates, benzoates, salicylates, ascorbates, and the like. Phenolate salts are the alkaline earth metal salts, sodium, potassium or lithium. The term “pharmaceutically acceptable salt” in this respect, refers to the relatively non-toxic, inorganic and organic acid or base addition salts of compounds of the present invention. These salts can be prepared in situ during the final isolation and purification of the compounds of the invention, or by separately reacting a purified compound of the invention in its free base or free acid form with a suitable organic or inorganic acid or base, and isolating the salt thus formed. Representative salts include the hydrobromide, hydrochloride, sulfate, bisulfate, phosphate, nitrate, acetate, valerate, oleate, palmitate, stearate, laurate, benzoate, lactate, phosphate, tosylate, citrate, maleate, fumarate, succinate, tartrate, napthylate, mesylate, glucoheptonate, lactobionate, and laurylsulphonate salts and the like. (See, e.g., Berge et al. (1977) “Pharmaceutical Salts”, J. Pharm. Sci. 66:1-19).

Aa salt or pharmaceutically acceptable salt is contemplated for all compounds disclosed herein.

As used herein, “treating” means preventing, slowing, halting, or reversing the progression of a disease or infection. Treating may also mean improving one or more symptoms of a disease or infection.

The compounds of the present invention may be administered in various forms, including those detailed herein. The treatment with the compound may be a component of a combination therapy or an adjunct therapy, i.e. the subject or patient in need of the drug is treated or given another drug for the disease in conjunction with one or more of the instant compounds. This combination therapy can be sequential therapy where the patient is treated first with one drug and then the other or the two drugs are given simultaneously. These can be administered independently by the same route or by two or more different routes of administration depending on the dosage forms employed.

As used herein, a “pharmaceutically acceptable carrier” is a pharmaceutically acceptable solvent, suspending agent or vehicle, for delivering the instant compounds to the animal or human. The carrier may be liquid or solid and is selected with the planned manner of administration in mind. Liposomes are also a pharmaceutically acceptable carrier.

The dosage of the compounds administered in treatment will vary depending upon factors such as the pharmacodynamic characteristics of a specific chemotherapeutic agent and its mode and route of administration; the age, sex, metabolic rate, absorptive efficiency, health and weight of the recipient; the nature and extent of the symptoms; the kind of concurrent treatment being administered; the frequency of treatment with; and the desired therapeutic effect.

A dosage unit of the compounds used in the method of the present invention may comprise a single compound or mixtures thereof with additional agents. The compounds can be administered in oral dosage forms as tablets, capsules, pills, powders, granules, elixirs, tinctures, suspensions, syrups, and emulsions. The compounds may also be administered in intravenous (bolus or infusion), intraperitoneal, subcutaneous, or intramuscular form, or introduced directly, e.g. by injection, topical application, or other methods, into or onto a site of infection, all using dosage forms well known to those of ordinary skill in the pharmaceutical arts.

The compounds used in the method of the present invention can be administered in admixture with suitable pharmaceutical diluents, extenders, excipients, or carriers (collectively referred to herein as a pharmaceutically acceptable carrier) suitably selected with respect to the intended form of administration and as consistent with conventional pharmaceutical practices. The unit will be in a form suitable for oral, rectal, topical, intravenous or direct injection or parenteral administration. The compounds can be administered alone or mixed with a pharmaceutically acceptable carrier. This carrier can be a solid or liquid, and the type of carrier is generally chosen based on the type of administration being used. The active agent can be co-administered in the form of a tablet or capsule, liposome, as an agglomerated powder or in a liquid form. Examples of suitable solid carriers include lactose, sucrose, gelatin and agar. Capsule or tablets can be easily formulated and can be made easy to swallow or chew; other solid forms include granules, and bulk powders. Tablets may contain suitable binders, lubricants, diluents, disintegrating agents, coloring agents, flavoring agents, flow-inducing agents, and melting agents. Examples of suitable liquid dosage forms include solutions or suspensions in water, pharmaceutically acceptable fats and oils, alcohols or other organic solvents, including esters, emulsions, syrups or elixirs, suspensions, solutions and/or suspensions reconstituted from non-effervescent granules and effervescent preparations reconstituted from effervescent granules. Such liquid dosage forms may contain, for example, suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweeteners, thickeners, and melting agents. Oral dosage forms optionally contain flavorants and coloring agents. Parenteral and intravenous forms may also include minerals and other materials to make them compatible with the type of injection or delivery system chosen.

Techniques and compositions for making dosage forms useful in the present invention are described in the following references: 7 Modern Pharmaceutics, Chapters 9 and 10 (Banker & Rhodes, Editors, 1979); Pharmaceutical Dosage Forms: Tablets (Lieberman at al., 1981); Ansel, Introduction to Pharmaceutical Dosage Forms 2nd Edition (1976); Remington's Pharmaceutical Sciences, 17th ed. (Mack Publishing Company, Easton, Pa., 1985); Advances in Pharmaceutical Sciences (David Ganderton, Trevor Jones, Eds., 1992); Advances in Pharmaceutical Sciences Vol. 7. (David Ganderton, Trevor Jones, James McGinity, Eds., 1995); Aqueous Polymeric Coatings for Pharmaceutical Dosage Forms (Drugs and the Pharmaceutical Sciences, Series 36 (James McGinity, Ed., 1989); Pharmaceutical Particulate Carriers: Therapeutic Applications: Drugs and the Pharmaceutical Sciences, Vol 61 (Alain Rolland, Ed., 1993); Drug Delivery to the Gastrointestinal Tract (Ellis Horwood Books in the Biological Sciences. Series in Pharmaceutical Technology; J. G. Hardy, S. S. Davis, Clive G. Wilson, Eds.); Modem Pharmaceutics Drugs and the Pharmaceutical Sciences, Vol 40 (Gilbert S. Banker, Christopher T. Rhodes, Eds.). All of the aforementioned publications are incorporated by reference herein.

Tablets may contain suitable binders, lubricants, disintegrating agents, coloring agents, flavoring agents, flow-inducing agents, and melting agents. For instance, for oral administration in the dosage unit form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic, pharmaceutically acceptable, inert carrier such as lactose, gelatin, agar, starch, sucrose, glucose, methyl cellulose, magnesium stearate, dicalcium phosphate, calcium sulfate, mannitol, sorbitol and the like. Suitable binders include starch, gelatin, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth, or sodium alginate, carboxymethylcellulose, polyethylene glycol, waxes, and the like. Lubricants used in these dosage forms include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride, and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum, and the like.

The compounds used in the method of the present invention may also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamallar vesicles, and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine, or phosphatidylcholines. The compounds may be administered as components of tissue-targeted emulsions.

The compounds used in the method of the present invention may also be coupled to soluble polymers as targetable drug carriers or as a prodrug. Such polymers include polyvinylpyrrolidone, pyran copolymer, polyhydroxylpropylmethacrylamide-phenol, polyhydroxyethylasparta-midephenol, or polyethyleneoxide-polylysine substituted with palmitoyl residues. Furthermore, the compounds may be coupled to a class of biodegradable polymers useful in achieving controlled release of a drug, for example, polylactic acid, polyglycolic acid, copolymers of polylactic and polyglycolic acid, polyepsilon caprolactone, polyhydroxy butyric acid, polyorthoesters, polyacetals, polydihydropyrans, polycyanoacylates, and crosslinked or amphipathic block copolymers of hydrogels.

Gelatin capsules may contain the active ingredient compounds and powdered carriers, such as lactose, starch, cellulose derivatives, magnesium stearate, stearic acid, and the like. Similar diluents can be used to make compressed tablets. Both tablets and capsules can be manufactured as immediate release products or as sustained release products to provide for continuous release of medication over a period of hours. Compressed tablets can be sugar coated or film coated to mask any unpleasant taste and protect the tablet from the atmosphere, or enteric coated for selective disintegration in the gastrointestinal tract.

For oral administration in liquid dosage form, the oral drug components are combined with any oral, non-toxic, pharmaceutically acceptable inert carrier such as ethanol, glycerol, water, and the like. Examples of suitable liquid dosage forms include solutions or suspensions in water, pharmaceutically acceptable fats and oils, alcohols or other organic solvents, including esters, emulsions, syrups or elixirs, suspensions, solutions and/or suspensions reconstituted from non-effervescent granules and effervescent preparations reconstituted from effervescent granules. Such liquid dosage forms may contain, for example, suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweeteners, thickeners, and melting agents.

Liquid dosage forms for oral administration can contain coloring and flavoring to increase patient acceptance. In general, water, a suitable oil, saline, aqueous dextrose (glucose), and related sugar solutions and glycols such as propylene glycol or polyethylene glycols are suitable carriers for parenteral solutions. Solutions for parenteral administration preferably contain a water soluble salt of the active ingredient, suitable stabilizing agents, and if necessary, buffer substances. Antioxidizing agents such as sodium bisulfite, sodium sulfite, or ascorbic acid, either alone or combined, are suitable stabilizing agents. Also used are citric acid and its salts and sodium EDTA. In addition, parenteral solutions can contain preservatives, such as benzalkonium chloride, methyl- or propyl-paraben, and chlorobutanol. Suitable pharmaceutical carriers are described in Remington's Pharmaceutical Sciences, Mack Publishing Company, a standard reference text in this field.

The compounds used in the method of the present invention may also be administered in intranasal form via use of suitable intranasal vehicles, or via transdermal routes, using those forms of transdermal skin patches well known to those of ordinary skill in that art. To be administered in the form of a transdermal delivery system, the dosage administration will generally be continuous rather than intermittent throughout the dosage regimen.

Parenteral and intravenous forms may also include minerals and other materials to make them compatible with the type of injection or delivery system chosen.

Each embodiment disclosed herein is contemplated as being applicable to each of the other disclosed embodiments. Thus, all combinations of the various elements described herein are within the scope of the invention.

This invention will be better understood by reference to the Experimental Details which follow, but those skilled in the art will readily appreciate that the specific experiments detailed are only illustrative of the invention as described more fully in the claims which follow thereafter.

Experimental Details

Materials and Methods

PR-FRET Assay for Retinol-Induced RBP4-TTR Interaction

Binding of a desired RBP4 antagonist displaces retinol and induces hindrance for RBP4-TTR interaction resulting in the decreased FRET signal (FIG. 7). Bacterially expressed MBP-RBP4 and untagged TTR were used in this assay. For the use in the TR-FRET assay the maltose binding protein (MBP)-tagged human RBP4 fragment (amino acids 19-201) was expressed in the Gold(DE3)pLysS E. coli strain (Stratagene) using the pMAL-c4x vector. Following cell lysis, recombinant RBP4 was purified from the soluble fraction using the ACTA FPLC system (GE Healthcare) equipped with the 5-ml the MBP Trap HP column. Human untagged TTR was purchased from Calbiochem. Untagged TTR was labeled directly with Eu³⁺ Cryptate-NHS using the HTRF Cryptate Labeling kit from CisBio following the manufacturer's recommendations. HTRF assay was performed in white low volume 384 well plates (Greiner-Bio) in a final assay volume of 16 μl per well. The reaction buffer contained 10 mM Tris-HCl pH 7.5, 1 mM DTT, 0.05% NP-40, 0.05% Prionex, 6% glycerol, and 400 mM KF. Each reaction contained 60 nM MBP-RBP4 and 2 nM TTR-Eu along with 26.7 nM of anti-MBP antibody conjugated with d2 (Cisbio). Titration of test compounds in this assay was conducted in the presence of 1 μM retinol. All reactions were assembled in the dark under dim red light and incubated overnight at +4° C. wrapped in aluminum foil. TR-FRET signal was measured in the SpectraMax M5e Multimode Plate Reader (Molecular Device). Fluorescence was excited at 337 nm and two readings per well were taken: Reading 1 for time-gated energy transfer from Eu(K) to d2 (337 nm excitation, 668 nm emission, counting delay 75 microseconds, counting window 100 microseconds) and Reading 2 for Eu(K) time-gated fluorescence (337 nm excitation, 620 nm emission, counting delay 400 microseconds, counting window 400 microseconds). The TR-FRET signal was expressed as the ratio of fluorescence intensity: Flu₆₆₅/Flu₆₂₀×10,000.

Scintillation Proximity RBP4 Binding Assay

Untagged human RBP4 purified from urine of tubular proteinuria patients was purchased from Fitzgerald Industries International. It was biotinylated using the EZ-Link Sulfo-NHS-LC-Biotinylation kit from Pierce following the manufacturer's recommendations. Binding experiments were performed in 96-well plates (OptiPlate, PerkinElmer) in a final assay volume of 100 μl per well in SPA buffer (1×PBS, pH 7.4, 1 mM EDTA, 0.1% BSA, 0.5% CHAPS). The reaction mix contained 10 nM ³H-Retinol (48.7 Ci/mmol; PerkinElmer), 0.3 mg/well Streptavidin-PVT beads, 50 nM biotinylated RBP4 and a test compound. Nonspecific binding was determined in the presence of 20 UM of unlabeled retinol. The reaction mix was assembled in the dark under dim red light. The plates were sealed with clear tape (TopSeal-A: 96-well microplate, PerkinElmer), wrapped in the aluminum foil, and allowed to equilibrate 6 hours at room temperature followed by overnight incubation at +4° C. Radiocounts were measured using a TopCount NXT counter (Packard Instrument Company).

General Procedures for Preparing N-Methyl-2-phenoxyethanamine Amide II

Conditions: A1) carboxylic acid, HBTU, Et₃N, DMF; A2) carboxylic acid, EDCI, HOBt, i-Pr₂NEt, DMF; A3) acid chloride, Et₃N, CH₂Cl₂.

General Procedure (GP-A1) for Carboxamide Formation:

A mixture of amine I (1 equiv), desired carboxylic acid (1 equiv), triethylamine (Et₃N) (3 equiv), and 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) (1.5 equiv) in DMF (0.25 M) was stirred at room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with EtOAc. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired carboxamide II. The product structure was verified by ¹H NMR and by mass analysis.

General Procedure (GP-A2) for Carboxamide Formation:

A mixture of amine I (1 equiv), desired carboxylic acid (1 equiv), N, N-diisopropylethylamine (i-Pr₂NEt) (3 equiv), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (1.5 equiv) and hydroxybenzotriazole (HOBt) (1.5 equiv) in DMF (0.25 M) was stirred at room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with EtOAc. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired carboxamide II. The product structure was verified by ¹H NMR and by mass analysis.

General Procedure (GP-A3) for Carboxamide Formation:

A mixture of amine I (1 equiv), Et₃N (3 equiv), and acid chloride (1 equiv) in CH₂Cl₂ (0.25 M) was stirred at room temperature until the reaction was complete by LC-MS. The mixture was washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired carboxamides II. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing N-Methyl-N-(2-phenoxyethyl)-4,5,6,7-tetrabydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide Carboxamides IV

Conditions: B) acid chloride, Et₃N, CH₂Cl₂. General Procedure (GP-B) for Carboxamide Formation:

A mixture of amine III (1 equiv), desired acid chloride (1 equiv) and triethylamine (Et₃N) (3 equiv) in CH₂Cl₂ (0.25 M) was stirred from 0° C. to room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired carboxamides IV. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing N-Methyl-N-(2-phenoxyethyl)-4,5,6,7-tetrabydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide Sulfonamides V

Conditions: C) sulfonyl chloride, i-Pr₂NEt, CH₂Cl₂. General Procedure (GP-C) for Sulfonamide Formation:

A mixture of amine III (1 equiv), desired sulfonyl chloride (1 equiv) and i-Pr₂NEt (3 equiv) in CH₂Cl₂ (0.25 M) was stirred from 0° C. to room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired sulfonamides V. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing Alkylated N-Methyl-N-(2-phenoxyethyl)-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide VI

Conditions: D) aldehyde or ketone, NaBH(OAc)₃, CH₂Cl₂. General Procedure (GP-D) for Sulfonamide Formation:

A mixture of amine III (1 equiv), desired aldehyde or ketone (1.5 equiv) and HOAc (6 equiv) in CH₂Cl₂ (0.25 M) was stirred for 16 hours at room temperature. To this was added sodium triacetoxyborohydride (NaBH(OAc)₃) and the mixture stirred at room temperature until the reaction was complete by LC-MS. The mixture was diluted with aqueous, saturated NaHCO₃ solution and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired amines VI. The product structure was verified by ¹H NMR and by mass analysis.

General Procedure for Preparing N-Methyl-N-(2-phenoxyethyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide Carboxamide VIII

Conditions: E) acid chloride, Et₃N, CH₂Cl₂. General Procedure (GP-E) for Carboxamide Formation:

A mixture of amine VII (1 equiv), desired acid chloride (1 equiv) and triethylamine (Et₃N) (3 equiv) in CH₂Cl₂ (0.25 M) was stirred from 0° C. to room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired carboxamides VIII. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing N-Methyl-N-(2-phenoxyethyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide Sulfonamides IX

Conditions: F) sulfonyl chloride, i-Pr₂NEt, CH₂Cl₂. General Procedure (GP-F) for Sulfonamide Formation:

A mixture of amine VII (1 equiv), desired sulfonyl chloride (1 equiv) and i-Pr₂NEt (3 equiv) in CH₂Cl₂ (0.25 M) was stirred from 0° C. to room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₂OH/concentrated NH₂OH) to afford the desired sulfonamides IX. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing Alkylated N-Methyl-N-(2-phenoxyethyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamides X

Conditions: G) aldehyde or ketone, NaBH(OAc)₃, CH₂Cl₂. General Procedure (GP-G) for Sulfonamide Formation:

A mixture of amine VII (1 equiv), desired aldehyde or ketone (1.5 equiv) and HOAc (6 equiv) in CH₂Cl₂ (0.25 M) was stirred for 16 hours at room temperature. To this was added NaBH(OAc)₃ and the mixture stirred at room temperature until the reaction was complete by LC-MS. The mixture was diluted with aqueous, saturated NaHCO₃ solution and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired amines X. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing N-Methyl-N-(2-phenoxyethyl)-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide Carboxamide XII

Conditions: H) acid chloride, Et₃N, CH₂Cl₂. General Procedure (GP-H) for Carboxamide Formation:

A mixture of amine XI (1 equiv), desired acid chloride (1 equiv) and Et₃N (3 equiv) in CH₂Cl₂ (0.25 M) was stirred from 0° C. to room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired carboxamides XII. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing N-Methyl-N-(2-phenoxyethyl)-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide Sulfonamides XIII

Conditions: I) sulfonyl chloride, i-Pr₂NEt, CH₂Cl₂. General Procedure (GP-I) for Sulfonamide Formation:

A mixture of amine XI (1 equiv), desired sulfonyl chloride (1 equiv) and i-Pr₂NEt (3 equiv) in CH₂Cl₂ (0.25 M) was stirred from 0° C. to room temperature until the reaction was complete by LC-MS. The mixture was diluted with H₂O and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired sulfonamides XIII. The product structure was verified by ¹H NMR and by mass analysis.

General Procedures for Preparing Alkylated (N-Methyl-N-(2-phenoxyethyl)-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamides XIV

Conditions: J) aldehyde or ketone, NaBH(OAc)₃, CH₂Cl₂. General Procedure (GP-J) for Sulfonamide Formation:

A mixture of amine XI (1 equiv), desired aldehyde or ketone (1.5 equiv) and HOAc (6 equiv) in CH₂Cl₂ (0.25 M) was stirred for 16 hours at room temperature. To this was added NaBH(OAc)₃ and the mixture stirred at room temperature until the reaction was complete by LC-MS. The mixture was diluted with aqueous, saturated NaHCO₃ solution and extracted with CH₂Cl₂. The combined organic extracts were washed with H₂O, brine, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by silica gel chromatography (typical eluents included either a mixture of or hexanes and EtOAc or a mixture of CH₂Cl₂ and a 90:9:1 mixture of CH₂Cl₂/CH₃OH/concentrated NH₄OH) to afford the desired amines XIV. The product structure was verified by ¹H NMR and by mass analysis.

Preparation of 2-(2-(Tert-butyl)phenoxy)-N-methylethanamine Hydrochloride (4)

Step A: To a −10° C. cooled suspension of 2-chloroethanamine hydrochloride (35.5 g, 0.306 mol) and NaHCO₂ (102.8 g, 1.22 mol) in THF (450 mL) and H₂O (450 mL (stirring in a 2-L, three-necked, round-bottomed flask equipped with a thermometer was carefully added a solution of di-tert-butyl dicarbonate (73.4 g, 0.336 mol) in THF (40 mL) dropwise over 30 minutes. The mixture was allowed to warm to room temperature and stirred for an additional 24 hours. The reaction was diluted with H₂O (200 mL) and extracted with EtOAc (3×150 mL). The combined organic extracts were washed with H₂O (100 mL), brine (100 mL), dried over Na₂SO₄, filtered, and concentrated under reduced pressure to give tert-butyl(2-chloroethyl)carbamate (2) as a clear, colorless oil that was used as is in the next step (60.96 g, quantitative %): ¹H NMR (500 MHz, CDCl₃) δ 4.89 (bs, 1H), 3.60 (m, 2H), 3.46 (m, 2H), 1.45 (s, 9H).

Step B: A 2-L, three-necked, round-bottomed flask equipped with a thermometer, reflux condenser, and mechanical stirrer was charged with tert-butyl(2-chloroethyl)carbamate (2, 65.28 g, 0.337 mol), 2-(tert-butyl)phenol (34.0 mL, 0.222 mol), KI (0.365 g, 2.20 mmol), Cs₂CO₃ (183 g, 0.560 mol), and DMF (700 mL) and the mixture was heated at 60° C. for 16 hours. The mixture was allowed to cool to room temperature and was diluted with H₂O (1 L) and extracted with EtOAc (3×200 mL). The combined organic extracts were washed with 5% aqueous LiCl solution (3×250 mL), brine (250 mL), dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The residue was purified over a plug of silica gel using a hexanes/EtOAc eluent system (0% to 15% EtOAc in hexanes) to give tert-butyl (2-(2-(tert-butyl)phenoxy)ethyl)carbamate (3) as a yellow solid (53.46 g, 82%): ¹H NMR (500 MHz, CDCl₃) δ 7.28 (m, 1H), 7.16 (m, 1H), 6.92 (m, 1H), 6.83 (m, 1H), 4.83 (bs, 1H), 4.07 (m, 2H), 3.59 (m, 2H), 1.39 (s, 9H).

Step C: To a 0° C. cooled solution of lithium aluminum hydride (LiAlH₄) in THF (1.0 M, 367 mL, 0.367 mol) in THF (350 mL) in a 3-L, three-necked, round-bottomed flask equipped with a thermometer was carefully added a solution of tert-butyl (2-(2-(tert-butyl)phenoxy)ethyl)carbamates (3, 43.06 g, 0.147 mol) in THF (100 mL). Upon complete addition, the mixture was allowed to warm to room temperature followed by heating at 60° C. for 16 hours. The reaction was allowed to cool back to room temperature and then further cooled to 0° C. The reaction was carefully quenched by slow addition of H₂O (15 mL), 15% aqueous NaOH solution (15 mL), followed by another bolus of H₂O (40 mL). The rate of quenching was done carefully so as to maintain an internal temperature below 25° C. The mixture stirred for 1 hour and was filtered through Celite. The aqueous filtrate was extracted with Et₂O (2×150 mL) and the organic extracts were combined, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The residue was purified by flash column chromatography (Isco CombiFlash Rf unit, two 330 g Redisep columns, 0% to 50% CH₂OH in CH₂Cl₂) to give 2-(2-(tert-butyl)phenoxy)-N-methylethanamine as an oil (13.44 g). This material was dissolved in Et₂O (250 mL) and treated with a solution of 2 M HCl in Et₂O (85 mL) at 0° C. The mixture stirred for 10 minutes at room temperature and was concentrated under reduced pressure to give 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride (4) as a white solid (15.38 g, 43%): ¹H NMR (500 mHz, DMSO-d₆) δ 9.14 (bs, 1H), 7.25 (m, 1H), 7.18 (m, 1H), 7.04 (m, 1H), 6.94 (m, 1H), 4.29 (m, 2H), 3.36 (m, 2H), 2.65 is, 3H), 1.34 (s, 9H).

Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide Hydrochloride (6)

Step A: To a solution of 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride (4, 0.225 g, 0.928 mmol), 6-(tert-butoxycarbonyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid (0.250 g, 0.928 mmol), and i-Pr₂NEt (0.49 mL, 2.78 mmol) in DMF (18 mL) under an atmosphere of N₂ was added EDCI (0.213 g, 1.11 mmol) and HOBt (0.150 g, 1.11 mmol). The resulting solution was stirred at room temperature for 18 hours, was diluted with H₂O (20 mL), and extracted with EtOAc (4×30 mL). The combined organic extracts were washed with brine (3×30 mL), dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The residue was chromatographed over silica gel (0% to 5% CH₃OH in CH₂Cl₂ with 0.01% NH₄OH) to give tert-butyl 3-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)carbamoyl)-4,5-dihydro-1H-pyrazolo[3,4-c]pyridine-6(7H)-carboxylate (5) as a white solid (0.365 g, 86%): ¹H NMR (300 MHz, DMSO-d₆) δ 12.99-12.95 (m, 1H), 7.24-7.10 (m, 2H), 7.03-6.93 (m, 1H), 6.90-6.80 (m, 1H), 4.52-4.41 (m, 3H), 4.22-4.14 (m, 2H), 3.92-3.85 (m, 1H), 3.58 (t, J=5.4 Hz, 2H), 3.48 (s, 1H), 3.03 (s, 2H), 2.69-2.61 (m, 2H), 1.41 (s, 9H), 1.31 (s, 3H), 1.16 (m, 6H); ESI MS m/z 457 [M+H]⁺.

Step B: To a suspension of tert-butyl 3-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)carbamoyl)-4,5-dihydro-1H-pyrazolo[3,4-c]pyridine-6(7H)-carboxylate (5, 0.250 g, 0.548 mmol) in CH₂Cl₂ (3.2 mL) was added 2N HCl solution in Et₂O (2 mL) and the resulting solution was stirred at room temperature for 6 hours. The mixture was concentrated under reduced pressure to provide N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide hydrochloride (6) as a white solid (198 mg, 92%): ¹H NMR (300 MHz, DMSO-d₆) δ 13.26 (s, 1H), 9.00 (s, 2H), 7.24-7.10 (m, 2H), 7.03-6.94 (m, 1H), 6.92-6.82 (m, 1H), 4.43 (t, J=6.0 Hz, 1H), 4.27-4.15 (m, 4H), 3.90 (t, J=5.4 Hz, 1H), 3.51 (s, 1.4H), 3.41-3.31 (m, 2H), 3.0 (s, 1.6H), 2.97-2.88 (m, 2H), 1.34-1.20 (m, 9H); ESI MS m/z 357 [M+H]⁺.

Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrabydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide Hydrochloride (8)

Step A: To a solution of 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride (4, 0.225 g, 0.928 mmol), 5-(tert-butoxycarbonyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid (0.250 g, 0.928 mmol), and i-Pr₂NEt (0.49 mL, 2.78 mmol) in DMF (18 mL) under an atmosphere of N₂ was added EDCI (0.213 g, 1.11 mmol) and HOBt (0.150 g, 1.11 mmol). The resulting solution was stirred at room temperature for 18 hours, was diluted with H₂O (20 mL), and extracted with EtOAc (4×30 mL). The combined organic extracts were washed with brine (3×30 mL), dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The residue was chromatographed over silica gel (0% to 5% CH₃OH in CH₂Cl₂ with 0.01% NH₄OH) to give tert-butyl 3-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)carbamoyl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate (7) as a white solid (0.365 g, 86%): ¹H NMR (300 MHz, DMSO-d₆) δ 12.99-12.95 (m, 1H), 7.24-7.10 (m, 2H), 7.03-6.93 (m, 1H), 6.90-6.80 (m, 1H), 4.52-4.41 (m, 3H), 4.22-4.14 (m, 2H), 3.92-3.85 (m, 1H), 3.58 (t, J=5.4 Hz, 2H), 3.48 (s, 1H), 3.03 (s, 2H), 2.69-2.61 (m, 2H), 1.41 (s, 9H), 1.31 (s, 3H), 1.16 (m, 6H); ESI MS m/z 457 [M+H]⁺.

Step B: To a suspension of tert-butyl 3-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)carbamoyl)-6,7-dihydro-1H-pyrazolo[4,3-c]pyridine-5(4H)-carboxylate (7, 0.365 g, 0.800 mmol) in a 1:1 mixture of CH₂Cl₂/CH₃OH (4.8 mL) was added a 2 N HCl solution in Et₂O (4.8 mL) and the resulting mixture was stirred at room temperature for 18 hours. The mixture was diluted with Et₂O (30 mL) and the solids were obtained by filtration, washed with Et₂O (30 mL), and dried under reduced pressure to provide N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide hydrochloride (8) as a white solid (0.203 g, 64%): ¹H NMR (300 MHz, DMSO-d₆) δ 13.27 (s, 1H), 9.10 (br s, 2H), 7.23-7.11 (m, 2H), 7.03-6.95 (m, 1H), 6.91-6.82 (m, 1H), 4.47-4.39 (m, 1H), 4.26-4.16 (m, 4H), 3.94-3.86 (m, 1H), 3.51 (s, 1.3H), 3.39-3.33 (m, 2H), 3.66 (s, 1.7H), 2.97-2.88 (m, 2H), 1.32-1.21 (m, 9H); ESI MS m/z 357 [M+H]⁺.

Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide Hydrochloride (10)

Step A: To a solution of 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride (4, 0.500 g, 2.05 mmol), 5-(tert-butoxycarbonyl)-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxylic acid (0.519 g, 2.05 mmol), and i-Pr₂NEt (0.791 g, 6.15 mmol) in DMF (36 mL) under an atmosphere of N₂ was added EDCI (0.417 g, 2.46 mmol) and HOBt (0.332 g, 2.46 mmol). The resulting solution was stirred at room temperature for 18 hours, was diluted with H₂O (30 mL), and extracted with EtOAc (4×30 mL). The combined organic extracts were washed with brine (3×30 mL) and concentrated under reduced pressure. The obtained solids were chromatographed over silica gel (0% to 100% EtOAc in hexanes) to give tert-butyl 3-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)carbamoyl)-4,6-dihydropyrrolo[3,4-c]pyrazole-5(1H)-carboxylate (9) as a white foam (563 mg, 62%): ¹H NMR (300 MHz, DMSO-d₆) δ 13.36-13.10 (m, 1H), 7.24-7.09 (m, 2H), 7.03-6.92 (m, 1H), 6.90-6.80 (m, 1H), 4.48-4.14 (m, 6.5H), 3.94-3.85 (m, 1.5H), 3.50 (s, 0.5H), 3.22-3.15 (m, 1H), 3.07-3.02 (m, 1.5H), 1.44 (s, 9H), 1.34-1.18 (m, 9H); ESI MS m/z 443 [M+H]⁺.

Step B: To a suspension of tert-butyl 3-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)carbamoyl)-4,6-dihydropyrrolo[3,4-c]pyrazole-5(1H)-carboxylate (9, 0.556 g, 1.26 mmol) in CH₂Cl₂ (7.5 mL) was added a 2 N HCl solution in Et₂O (7.5 mL) and the resulting mixture was stirred at room temperature for 18 hours. The mixture was diluted with Et₂O (30 mL) and the solids were obtained by filtration. The solids were washed with Et₂O (30 mL) and dried under reduced pressure to provide N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide hydrochloride (10) as an off-white powder (394 mg, 82%): NMR (300 MHz, DMSO-d₆) δ 10.41-10.19 (m, 2H), 7.24-7.11 (m, 2H), 7.04-6.94 (m, 1H), 6.91-6.82 (m, 1H), 5.92-4.73 (m, 2H), 4.40-4.28 (m, 4H), 4.25-4.14 (m, 2.5H), 3.94-3.86 (m, 1H), 3.28 (s, 1.5H), 3.03 (s, 1H), 1.34-1.15 (m, 9H); ESI MS m/z 343 [M+H]⁺.

Example 1: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-6-methoxy-N-methyl-[1,2,4]triazolo[4,3-a]pyridine-3-carboxamide (11)

Step A: A solution of 2-hydrazinyl-5-methoxypyridine (0.674 g, 4.84 mmol) and ethyl 2-oxoacetate (50% in toluene, 0.988 g, 4.84 mmol) in CH₃OH (25 mL) was heated at 60 BC for 1 hour, then cooled to room temperature and concentrated under reduced pressure. The residue was dissolved in CH₂Cl₂ (25 mL) and PhI(OAc)₂ (1.71 g, 5.32 mmol) was added. The resulting mixture stirred for 16 hours then concentrated under reduced pressure. The residue was chromatographed over silica gel (0% to 80% EtOAc in hexanes) to give ethyl 6-methoxy-[1,2,4]triazolo[4,3-a]pyridine-3-carboxylate as an off-white solid (0.937 g, 87%): ¹H NMR (300 MHz, CDCl₃) δ 8.69 (dd, J=2.2, 0.6 Hz, 1H), 7.84 (dd, J=9.8, 0.7 Hz, 1H), 7.27 (dd, J=9.8, 2.3 Hz, 1H), 4.58 (q, J=7.1 Hz, 2H), 3.92 (s, 3H), 1.52 (t, J=7.1 Hz, 3H); MS (ESI+) m/z 222 [M+H]⁺.

Step 8: To a solution of ethyl 6-methoxy-[1,2,4]triazolo[4,3-a]pyridine-3-carboxylate (0.060 g, 0.271 mmol) in THF (5 mL) was added a solution of LiOH.H₂O (0.034 g, 0.813 mmol) in H₂O (3 mL). The mixture was stirred for 1 hour, was acidified to pH 6 with 2 N HCl, followed by concentration under reduced pressure. The residue was added to a mixture of 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride (4, 0.198 g, 0.813 mmol), benzotriazole-1-yl-oxy-tris-(dimethylamino)-phosphonium hexafluorophosphate (0.719 g, 1.62 mmol), and i-Pr₂NEt (0.424 mL, 2.43 mmol) in DMF (20 mL). The mixture was stirred at room temperature for 16 hours and then poured into H₂O (100 mL). The mixture was extracted with EtOAc (3×50 mL) and the combined organic extracts were washed with brine (3×30 mL), dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (0% to 50% EtOAc in hexanes) to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-6-methoxy-N-methyl-[1,2,4]triazolo[4,3-a]pyridine-3-carboxamide as a white solid (0.077 g, 25%): ¹H NMR (300 MHz, CDCl₃) δ 8.79 (m, 1H), 7.76 (m, 1H), 7.20 (m, 3H), 6.90 (m, 2H), 4.76 (m, 1H), 4.37 (m, 1H), 4.12 (m, 1H), 3.87 (m, 3H), 3.35 (m, 1H), 1.57 (s, 6H), 1.38 (s, 2H), 1.23 (s, 4H); MS (ESI+) m/z 383 [M+H]⁺.

Example 2: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-1H-1,2,3-triazole-5-carboxamide (12)

Step A: Following general procedure GP-A1, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and 1H-1,2,3-triazole-5-carboxylic acid were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-1H-1,2,3-triazole-5-carboxamide as a white solid (0.051 g, 81%): mp 148-151° C.; ¹H NMR (300 MHz, DMSO-d₆) δ 15.42 (br s, 1H), 8.19 (br s, 1H), 7.21-7.18 (m, 2H), 7.03-6.95 (m, 1H), 6.89-6.82 (m, 1H), 4.36 (br s, 1H), 4.22-4.20 (m, 2H), 3.95-3.91 (m, 1H), 3.40-3.33 (m, 1H), 3.08 (s, 3H), 1.31-1.17 (m, 9H); MS (ESI+) m/z 303 [M+H]⁺.

Example 3: Preparation of 2-((2-(2-(Tert-butyl)phenoxy)ethyl)(methyl)amino)-2-oxoacetic Acid (13)

Step A: Following general procedure GP-A3, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and ethyl 2-chloro-2-oxoacetate were converted to ethyl 2-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)amino)-2-oxoacetate as a clear oil (97.3 mg, 54%): ¹H NMR (300 MHz, CDCl₂) δ 7.32-7.24 (m, 1H), 7.21-7.14 (m, 1H), 6.98-6.82 (m, 2H), 4.40-4.27 (m, 2H), 4.25-4.18 (m, 2H), 3.90-3.76 (m, 2H), 3.18-3.10 (m, 3H), 1.39-1.30 (m, 12H); ESI MS m/z 308 [M+H]⁺.

Step B: To a solution of ethyl 2-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)amino)-2-oxoacetate (0.095 g, 0.309 mmol) in THF (6.0 mL) and CH₂OH (2.8 mL) was added a solution of LiOH.H₂O (0.129 g, 3.09 mmol) in H₂O (1.42 mL). The mixture stirred for 18 hours and was acidified with 2 N HCl, diluted with H₂O (10 mL), and extracted with Et₂O (3×20 mL). The combined organic extracts were dried over Na₂SO₄, filtered, and concentrated to provide 2-((2-(2-(tert-butyl)phenoxy)ethyl)(methyl)amino)-2-oxoacetic acid as a white solid (57.3 mg, 66%): op 98-101° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 14.11 (br s, 1H), 7.23-7.20 (m, 1H), 7.18-7.13 (m, 1H), 7.00-6.97 (m, 1H), 6.90-6.85 (m, 1H), 4.20-4.13 (m, 2H), 3.79-3.71 (m, 2H), 3.05 (s, 1.7H), 2.95 (s, 1.3H), 1.33-1.30 (m, 9H); ESI MS m/z 278 [M−H]⁻.

Example 4: Preparation of 2-(3-(2-(2-(Tert-butyl)phenoxy)ethyl)-3-methylureido)benzoic Acid (14)

Step A: To a solution of 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride (4, 0.066 g, 0.319 mmol) and Et₃N (0.038 g, 0.383 mmol) in CH₂Cl₂ (3.0 mL) was added methyl 2-isocyanatobenzoate (0.062 g, 0.350 mmol) and the mixture was stirred for 18 hours at room temperature. The mixture was diluted with H₂O (30 mL), extracted with CH₂Cl₂ (3×30 mL), and the combined organic extracts were concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (0% to 5% CH₂OH in CH₂Cl₂ with 0.01% NH₄OH) to give methyl 2-(3-(2-(2-(tert-butyl)phenoxy)ethyl)-3-methylureido)benzoate as a white solid (57 mg, 46%): ¹H NMR (300 MHz, CDCl₃) δ 10.74 (s, 1H), 8.60 (dd, J=9.0, 1.2 Hz, 1H), 8.00 (dd, J=8.1, 1.8 Hz, 1H), 7.55-7.47 (m, 1H), 7.30-7.26 (m, 1H), 7.20-7.12 (m, 1H), 7.02-6.94 (m, 1H), 6.93-6.86 (m, 2H), 4.23 (t, J=5.4 Hz, 2H), 3.93-3.87 (m, 5H), 3.27 (s, 3H), 1.38 (s, 9H); ESI MS m/z 385 [M+H]⁺.

Step B: To a solution of methyl 2-(3-(2-(2-(tert-butyl)phenoxy)ethyl)-3-methylureido)benzoate (0.054 g, 0.141 mmol) in THF (2.7 mL) and CH₂OH (1.3 mL) was added a solution of LiOH.H₂O (0.059 g, 1.41 mmol) in H₂O (0.66 mL) and the mixture stirred at room temperature for 18 hours. The mixture was acidified with 2 N HCl, diluted with H₂O (10 mL), and extracted with Et₂O (4×20 mL). The combined organic extracts were dried over Na₂SO₄, filtered, and concentrated to provide 2-(3-(2-(2-(tert-butyl)phenoxy)ethyl)-3-methylureido)benzoic acid as a white solid (37 mg, 97%) mp 136-141° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.50 (s, 1H), 10.93 (s, 1H), 8.48 (dd, J=8.5, 0.5 Hz, 1H), 7.95 (dd, J=8.0, 1.5 Hz, 1H), 7.56-7.50 (m, 1H), 7.21-7.13 (m, 2H), 7.02-6.97 (m, 2H), 6.88-6.83 (m, 1H), 4.15 (t, J=6.00 Hz, 2H), 3.82 (t, J=6.0 Hz, 2H), 3.11 (s, 3H), 1.28 (s, 9H); ESI MS m/z 371 [M+H]⁺.

Example 5: Preparation of 2-(3-Methyl-3-(2-(2-(trifluoromethyl) phenoxy)ethyl)ureido)benzoic Acid (15)

Step A: To a solution of N-methyl-2-(2-(trifluoromethyl) phenoxy)ethanamine (0.058 g, 0.265 mmol) and Et₃N (0.027 g, 0.265 mmol) in CH₂Cl₂ (0.9 mL) was added methyl 2-isocyanatobenzoate (0.047 g, 0.265 mmol). The mixture stirred at room temperature for 2 hours, was diluted with H₂O (30 mL), and extracted with CH₂Cl₂ (3×30 mL). The combined organic extracts were concentrated under reduced pressure and the resulting residue was chromatographed over silica gel (0% to 50% EtOAc in hexanes) to give methyl 2-(3-methyl-3-(2-(2-(trifluoromethyl)phenoxy)ethyl) ureido)benzoic acid as a white solid (84 mg, 79%): ¹H NMR (300 MHz, DMSO-d₆) δ 10.41 (s, 1H), 8.43 (dd, J=8.7, 0.9 Hz, 1H), 7.94 (dd, J=7.8, 1.5 Hz, 1H), 7.66-7.52 (m, 3H), 7.30 (d, J=8.7 Hz, 1H), 7.13-7.00 (m, 2H), 4.27 (t, J=5.4 Hz, 2H), 3.85 (s, 3H), 3.76 (t, J=5.4 Hz, 2H), 3.13 (s, 3H); ESI MS m/z 397 [M+H]⁺.

Step B: To a solution of 2-(3-methyl-3-(2-(2-(trifluoromethyl)phenoxy)ethyl)ureido)benzoic acid (0.084 g, 0.211 mmol) in THF (4.2 mL) and CH₂OH (1.9 mL) was added a solution of LiOH.H₂O (0.089 g, 2.11 mmol) in H₂O (0.98 mL). The mixture stirred at room temperature for 4 hours, was acidified with 2 N HCl, and diluted with H₂O (20 mL). The resulting precipitate was collected by filtration, washed with 820 (30 mL), and dried under reduced pressure to provide 2-(3-(2-(2-(tert-butyl)phenoxy)ethyl)-3-methylureido)benzoic acid as a white solid (46 mg, 57%): mp 171-173° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.51 (br s, 1H), 10.89 (s, 1H), 8.46 (dd, J=8.5, 0.5 Hz, 1H), 7.96 (dd, J=8.0, 1.5 Hz, 1H), 7.64-7.58 (m, 2H), 7.54-7.49 (m, 1H), 7.29 (d, J=8.5 Hz, 1H), 7.11-7.06 (m, 1H), 7.02-6.97 (m, 1H), 4.27 (t, J=5.5 Hz, 2H), 3.75 (t, J=5.5 Hz, 2H), 3.11 (s, 3H); ESI MS m/z 381 [M−H]⁻.

Example 6: Preparation of 2-(3-(2-(2-(Tert-butyl)-4-chlorophenoxy)ethyl)-3-methylureido)benzoic Acid (16)

Step A: To a solution of 2-(2-(tert-butyl)-4-chlorophenoxy)-N-methylethanamine (0.101 g, 0.418 mmol) and Et₃N (0.051 g, 0.502 mmol) in CH₂Cl₂ (4.0 mL) was added methyl 2-isocyanatobenzoate (0.081 g, 0.459 mmol). The mixture stirred at room temperature for 18 hours, was diluted with H₂O (10 mL), and extracted with CH₂Cl₂ (3×10 mL). The combined organic extracts were concentrated under reduced pressure and the resulting residue was chromatographed over silica gel (0% to 20% EtOAc in hexanes) to give methyl 2-(3-(2-(2-(tert-butyl)-4-chlorophenoxy)ethyl)-3-methylureido)benzoate as a white solid (153 mg, 87%): ¹H NMR (300 MHz, DMSO-d₆) δ 10.47 (s, 1H), 8.45 (dd, J=8.7, 0.9 Hz, 1H), 7.94 (dd, J=8.1 1.5 Hz, 1H), 7.61-7.52 (m, 1H), 7.25-7.18 (m, 1H), 7.15-7.11 (m, 1H), 7.08-7.00 (m, 28), 4.16 (t, J=5.7 Hz, 2H), 3.87-3.78 (m, 5H), 3.11 (s, 3H), 1.26 (s, 9H); ESI MS m/z 419 [M+]⁺.

Step 8: To a solution of methyl 2-(3-(2-(2-(tert-butyl)-4-chlorophenoxy)ethyl)-3-methylureido)benzoate (0.150 g, 0.358 mmol) in THF (7.1 mL) and CH₃OH (3.3 mL) was added a solution of LiOH.H₂O (0.150 g, 3.58 mmol) in H₂O (1.6 mL). The mixture stirred at room temperature for 1.5 hours, acidified with 2 N HCl, and diluted with H₂O (30 mL). The resulting precipitate was collected by filtration, washed with H₂O (70 mL), and dried under reduced pressure to provide 2-(3-(2-(2-(tert-butyl)-4-chlorophenoxy)ethyl)-3-methylureido) benzoic acid as a white solid (121 mg, 84%); mp 166-169° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.50 (br s, 1H), 10.92 (s, 1H), 8.47 (dd, J=8.5, 0.5 Hz, 1H), 7.95 (dd, J=8.0, 1.5 Hz, 1H), 7.55-7.50 (m, 1H), 7.21 (dd, J=8.5, 2.5 Hz, 1H), 7.31 (d, J=2.5 Hz, 1H), 7.06-6.98 (m, 2H), 4.16 (t, J=6.0 Hz, 2H), 3.81 (t, J=6.0 Hz, 2H), 3.10 (s, 3H), 1.26 (s, 9H); ESI MS m/z 405 [M+H]⁺.

Example 7: Preparation of 2-(3-(2-(2-Isopropylphenoxy)ethyl)-3-methylureido)benzoic Acid (17)

Step A: To a solution of 2-(2-isopropylphenoxy)-N-methylethanamine hydrochloride (0.070 g, 0.304 mmol) and Et₃N (0.061 g, 0.608 mmol) in CH₂Cl₂ (2.9 mL) was added methyl 2-isocyanatobenzoate (0.054 g, 0.304 mmol). The mixture stirred at room temperature for 3 hours, was diluted with H₂O (10 mL), and extracted with CH₂Cl₂ (3×30 mL). The combined organic extracts were washed with brine (3×30 mL) and concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (0% to 50% EtOAc in hexanes) to give methyl 2-(3-(2-(2-isopropylphenoxy)ethyl)-3-methylureido)benzoate as a white solid (67 mg, 59%); ¹H NMR (500 MHz, DMSO-d₆) δ 10.48 (s, 1H), 8.49-8.39 (m, 1H), 7.95 (dd, J=8.0, 1.5 Hz, 1H), 7.59-7.54 (m, 1H), 7.17-7.09 (m, 2H), 7.06-7.01 (m, 1H), 6.94 (d, J=7.0 Hz, 1H), 6.90-6.86 (m, 1H), 4.13 (t, J=5.0 Hz, 2H), 3.89-3.84 (m, 3H), 3.79 (t, J=5.5 Hz, 2H), 3.23-3.15 (m, 1H), 3.13-3.08 (m, 38), 1.05-0.99 (m, 6H); ESI MS m/z 371 [M+H]⁺.

Step B: To a solution of methyl 2-(3-(2-(2-isopropylphenoxy)ethyl)-3-methylureido)benzoate (0.047 g, 0.175 mmol) in THF (3.4 mL) and CH₃OH (1.6 mL) was added a solution of LiOH.H₂O (0.073 g, 1.75 mmol) in H₂O (0.8 mL). The mixture stirred at room temperature for 4 hours, was acidified with 1 N HCl, and diluted with H₂O (30 mL). The resulting precipitate was collected by filtration, washed with H₂O (30 mL), and dried under reduced pressure to provide 2-(3-(2-(2-isopropylphenoxy)ethyl)-3-methylureido)benzoic acid as a white solid (38.1 mg, 61%): nip 146-149° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.49 (s, 1H), 10.95 (s, 1H), 8.50 (d, J=8.0 Hz, 1H), 7.95 (dd, J=8.0, 1.0 Hz, 1H), 7.56-7.49 (m, 1H), 7.16-7.08 (m, 2H), 7.03-6.97 (m, 1H), 6.93 (d, J=8.0 Hz, 1H), 6.91-6.85 (m, 1H), 4.13 (t, J=5.0 Hz, 2H), 3.78 (t, J=5.0 Hz, 2H), 3.25-3.14 (m, 1H), 3.10 (s, 3H), 1.03 (d, J=7.0 Hz, 6H); ESI MS m/z 357 [M+H]⁺.

Example 8: Preparation of 4-(3-(2-(2-(tert-butyl)phenoxy)ethyl)-3-methylureido)nicotinic Acid (18)

Step A: To a −78° C. cooled solution of triphosgene (0.144 g, 0.485 mmol) in CH₂Cl₂ (3.0 mL) was slowly added pyridine (0.077 g, 0.970 mmol) and the resulting solution was stirred at −78° C. for 10 minutes. A solution of 2-(2-(tert-butyl)phenoxy)-N-methylethanamine (0.201 g, 0.970 mmol) in CH₂Cl₂ (2.0 mL) was added and the resulting solution was stirred at −78° C. for 30 minutes. The solution was warmed to room temperature and stirred for an additional 1.5 hours. The reaction was diluted with 1 N HCl (5 mL) and extracted with CH₂Cl₂ (3×10 mL). The combined organic extracts were washed with saturated NaHCO₃ solution (40 mL) and concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (0% to 30% EtOAc in hexanes) to give (2-(2-(tert-butyl)phenoxy)ethyl)(methyl)carbamic chloride as a clear oil (110 mg, 42%): ¹H NMR (500 MHz, DMSO-d₆) δ 7.24-7.20 (m, 1H), 7.19-7.14 (m, 1H), 7.03-6.96 (m, 1H), 6.91-6.85 (m, 1H), 4.22-4.15 (m, 2H), 3.97 (t, J=5.5 Hz, 1H), 3.85 (t, J=5.5 Hz, 1H), 3.17 (s, 1.7H), 3.06 (s, 1.3H), 1.34-1.29 (m, 9H).

Step B: To a solution of (2-(2-(tert-butyl)phenoxy)ethyl) (methyl)carbamic chloride (0.105 g, 0.390 mmol) in THF (2.0 mL) was added i-Pr₂NEt (0.050 g, 0.390 mmol) and methyl 4-aminonicotinate (0.059 g, 0.390 mmol). The resulting solution was heated at 68° C. for 5 hours. The reaction was diluted with H₂O (10 mL) and extracted with EtOAc (4×30 mL). The combined organic extracts were concentrated under reduced pressure and the resulting residue was chromatographed over silica gel (0% to 5% CH₃OH in CH₂Cl₂ with 0.01% NH₄OH) to give methyl 4-(3-(2-(2-(tert-butyl)phenoxy)ethyl)-3-methylureido)nicotinate as a white solid (97 mg, 64%): ¹H NMR (500 MHz, DMSO-d₆) δ 10.64 (s, 1H), 8.97 (s, 1H), 8.53 (d, J=6.0 Hz, 1H), 8.40 (d, J=6.0 Hz, 1H), 7.23-7.12 (m, 2H), 7.02-6.99 (m, 1H), 6.88-6.84 (m, 1H), 4.17 (1, J=5.5 Hz, 2H), 3.89 (s, 3H), 3.84 (t, J=6.0 Hz, 2H), 3.13 (s, 3H), 1.26 (s, 9H); ESI MS m/z 386 [M+H]⁺.

Step C: To a solution of methyl 4-(3-(2-(2-(tert-butyl)phenoxy) ethyl)-3-methylureido)nicotinate (0.095 g, 0.247 mmol) in THF (4.9 mL) and CH₃OH (2.3 mL) was added a solution of LiOH.H₂O (0.103 g, 2.47 mmol) in H₂O (1.1 mL). The mixture stirred at room temperature for 3 hours, was acidified with 1 N HCl, and diluted with H₂O (20 mL). The resulting precipitate was collected by filtration, washed with H₂O (30 mL), and dried under reduced pressure to provide 4-(3-(2-(2-(tert-butyl)phenoxy)ethyl)-3-methylureido)nicotinic acid as a white solid (78 mg, 85%): mp 218-220° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 14.02 (br s, 1H), 8.92 (s, 1H), 8.52 (d, J=6.0 Hz, 1H), 8.47 (d, J=6.5 Hz, 1H), 7.22-7.13 (m, 2H), 7.00 (dd, J=8.0, 1.0 Hz, 1H), 6.89-6.84 (m, 1H), 4.17 (t, J=5.5 Hz, 2H), 3.85 (t, J=5.0 Hz, 2H), 3.12 (s, 3H), 1.25 (s, 9H); ESI MS m/z 372 [M+H]⁺.

Example 9: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methylpyrimidine-2-carboxamide (19)

Step A: Following general procedure GP-A2, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and pyrimidine-2-carboxylic acid were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methylpyrimidine-2-carboxamide as a clear viscous oil (89 mg, 69%); ¹H NMR (500 MHz, DMSO-d₆) δ 8.88 (dd, J=7.5, 5.0 Hz, 2H), 7.60-7.56 (m, 1H), 7.25-7.16 (m, 1.58), 7.14-7.09 (m, 0.5H), 7.05 (dd, J=8.5, 1.0 Hz, 0.5H), 6.91-6.83 (m, 1.5H), 4.24 (t, J=6.0 Hz, 1H), 4.12 (t, J=6.5 Hz, 1H), 3.93 (t, J=6.5 Hz, 1H), 3.55 (t, J=6.5 Hz, 1H), 3.12 (s, 1.5H), 2.90 (s, 1.5H), 1.35 (s, 5H), 1.24 (s, 4H); ESI MS m/z 314 [M+H]⁺.

Example 10: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methylpyrimidine-2-carboxamide (20)

Step A: Following general procedure GP-A2, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and pyridazine-3-carboxylic acid were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methylpyridazine-3-carboxamide as a white semi-solid (77 mg, 60%): ¹H NMR (500 MHz, DMSO-d₆) δ 9.32-9.28 (m, 1H), 7.87-7.79 (m, 2H), 7.25-7.16 (m, 1.5H), 7.11-7.04 (m, 1H), 6.91-6.82 (m, 1.5H), 4.28 (t, J=5.5 Hz, 1H), 4.19 (t, J=6.0 Hz, 1H), 3.99 (t, J=6.0 Hz, 1H), 3.89 (t, J=6.0 Hz, 1H), 3.16 (s, 1.5H), 3.09 (s, 1.5H), 1.34 (s, 4.5H), 1.21 (s, 4.5H); ESI MS m/z 314 [M+H]⁺.

Example 11: Preparation of N-(2-(2-(Tert-butyl)-4-chlorophenoxy) ethyl)-N-methylimidazo[1,2-b]pyridazine-2-carboxamide (21)

Step A: Following general procedure GP-A1, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and imidazo[1,2-b]pyridazine-2-carboxylic acid were combined to give N-(2-(2-(tert-butyl)-4-chlorophenoxy)ethyl)-N-methylimidazo[1,2-b]pyridazine-2-carboxamide as a white solid (75.8 mg, 72%): mp 73-78° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 8.61-8.52 (m, 2H), 8.21-8.11 (m, 1H), 7.30 (dd, J=9.5, 4.5 Hz, 1H), 7.24-6.97 (m, 3H), 4.57 (t, J=6.0 Hz, 1H), 4.28-4.21 (m, 2H), 3.94 (t, J=5.5 Hz, 1H), 3.51 (s, 1H), 3.10 (s, 2H), 1-31 (s, 3.5H), 1.10 (s, 5.5H); ESI MS m/z 387 [M+H]⁺.

Example 12: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-5-fluoro-N-methyl-1H-indazole-3-carboxamide (22)

Step A: Following general procedure GP-A2, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and 5-fluoro-1H-indazole-3-carboxylic acid were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-5-fluoro-N-methyl-1H-indazole-3-carboxamide as a white solid (123 mg, 69%): mp 186-190° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.65 (br s, 1H), 7.73-7.69 (m, 1H), 7.67-7.61 (m, 1H), 7.34-7.28 (m, 1H), 7.23-7.09 (m, 2H), 7.07-7.02 (m, 0.5H), 6.99-6.94 (m, 0.5H), 6.89-6.80 (m, 1H), 4.49 (t, J=5.5 Hz, 1H), 4.29-4.22 (m, 2H), 4.00 (t, J=5.5 Hz, 1H), 3.52 (s, 1.3H), 3.15 (s, 1.7H), 1.31 (s, 4H), 1.09 (s, 5H); ESI MS m/z 370 [M+H]⁺.

Example 13: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methylimidazo[1,2-b]pyridazino-2-carboxamide (23)

Step A: Following general procedure GP-A2, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and imidazo[1,2-b]pyridazine-2-carboxylic acid were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methylimidazo[1,2-b]pyridazine-2-carboxamide as a white solid (55.8 mg, 33%): mp 75-80° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 8.61-8.53 (m, 2H), 8.21-8.11 (m, 1H), 7.30 (dd, J=9.5, 4.5 Hz, 1H), 7.24-6.92 (m, 3H), 6.91-6.78 (m, 1H), 4.56 (t, J=5.5 Hz, 1H), 4.28-4.19 (m, 2H), 3.94 (t, J=6.0 Hz, 1H), 3.52 (s, 1.2H), 3.11 (s, 1.8H), 1.32 (s, 3.5H), 1.11 (s, 5.5H); ESI MS m/z 353 [M+H]⁺.

Example 14: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-1H-pyrazolo[3,4-b]pyridine-3-carboxamide (24)

Step A: Following general procedure GP-A2, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and 1H-pyrazolo[3,4-b]pyridine-3-carboxylic were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-1H-pyrazolo[3,4-b]pyridine-3-carboxamide as a white solid (61 mg, 60%): mp 157-159° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 14.12-14.06 (m 1H), 8.60-8.57 (m, 1H), 8.46-8.41 (m, 1H), 7.33-7.28 (m, 1H), 7.23-7.10 (m, 2H), 7.07-6.95 (m, 1H), 6.89-6.79 (m, 1H), 4.52 (t, J=5.5 Hz, 1H), 4.31-4.22 (m, 2H), 4.01 (t, J=6.0 Hz, 1H), 3.53 (s, 1.3H), 3.15 (s, 1.7H), 1.30 (s, 4H), 1.15 (s, 5H); ESI MS m/z 353 [M+H]⁺.

Example 15: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-6,8-dihydro-5H-[1,2,4]triazolo[3,4-c][1,4]oxazine-3-carboxamide (25)

Step A: To a solution of ethyl 6,8-dihydro-5H-[1,2,4]triazolo[3,4-c][1,4]oxazine-3-carboxylate (0.058 g, 0.294 mmol) in THF (2.4 mL) was added a solution of LiOH.H₂O (0.024 g, 0.588 mmol) in H₂O (1.6 mL) and the resulting solution was stirred at room temperature for 20 minutes. The reaction mixture was acidified to pH 6 with 2 N HCl and then concentrated under reduced pressure. The obtained residue was dissolved in DMF (3.2 mL) and to the solution was added 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride (4, 0.072, 0.394 mmol), i-Pr₂NEt (0.113 g, 0.882 mmol) and BOP (0.206 g, 0.588 mmol). The resulting solution was stirred at room temperature for 18 hours, was diluted with H₂O (30 mL), and extracted with EtOAc (4×30 mL). The combined organic extracts were washed with brine (3×20 mL) and concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (0% to 5% CH₃OH in CH₂Cl₂ with 0.01% NH₄OH) followed by a second chromatography over silica gel (0-1% CH₃OH in CH₂Cl₂ with 0.01% NH₄OH) to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-6,8-dihydro-5H-[1,2,4]triazolo[3,4-c][1,4]oxazine-3-carboxamide as a white solid (59 mg, 54%): mp 116-120° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 7.25-7.11 (m, 2H), 7.04-6.94 (m, 1H), 6.90-6.84 (m, 1H), 4.95-4.91 (m, 2H), 4.44 (t, J=6.0 Hz, 1H), 4.29-4.21 (m, 2H), 4.19 (t, J=5.0 Hz, 1H), 4.14 (t, J=5.5 Hz, 1H), 3.99-3.92 (m, 3H), 3.48 (s, 1.2H), 3.12 (s, 1.8H), 1.31 (s, 4H), 1.21 (s, 5H); ESI MS m/z 359 [M+H]⁺.

Example 16: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N,1-dimethyl-1,4,6,7-tetrahydropyrano[4,3-c]pyrazole-3-carboxamide (26)

Step A: Following general procedure GP-A2, 2-(2-(tert-butyl)phenoxy)-N-methylethanamine hydrochloride and 1-methyl-1,4,6,7-tetrahydropyrano[4,3-c]pyrazole-3-carboxylic acid were converted to N-(2-(2-(tert-butyl)phenoxy)ethyl)-N,1-dimethyl-1,4,6,7-tetrahydropyrano[4,3-c]pyrazole-3-carboxamide as a clear viscous oil (72 mg, 65%): ¹H NMR (500 MHz, DMSO-d₆) δ 7.23-7.10 (m, 2H), 6.99 (d, J=8.0 Hz, 1H), 6.89-6.81 (m, 1H), 4.61-4.59 (m, 2H), 4.47 (t, J=5.5 Hz, 2H), 4.42-4.14 (m, 2H), 3.89-3.77 (m, 2H), 3.76-3.68 (m, 3H), 3.50 (s, 1H), 3.02 (s, 2H), 2.70-2.66 (m, 2H), 1.33-1.17 (m, 9H); ESI MS m/z 372 [M+H]⁺.

Example 17: Preparation of 2-(3-(2-(2-(Tert-butyl)-4-fluorophenoxy) ethyl)-3-methylureido)benzoic Acid (27)

Step A: To a solution of 2-(2-(tert-butyl)-4-fluorophenoxy)-N-methylethanamine hydrochloride (4, 0.085 g, 0.326 mmol) and Et₃N (0.066 g, 0.651 mmol) in CH₂Cl₂ (1.1 mL) was added methyl 2-isocyanatobenzoate (0.064 g, 0.326 mmol). The mixture stirred at room temperature for 3 hours, was diluted with H₂O (10 mL), and extracted with CH₂Cl₂ (4×10 mL). The combined organic extracts were concentrated under reduced pressure and the resulting residue was chromatographed over silica gel (0% to 20% EtOAc in hexanes) to give methyl 2-(3-(2-(2-(tert-butyl)-4-fluorophenoxy)ethyl)-3-methylureido)benzoate as a white solid (116 mg, 88%): ¹H NMR (300 MHz, CDCl₃) δ 10.74 (s, 1H), 8.60 (d, J=8.7 Hz, 1H), 8.00 (dd, J=8.1, 1.5 Hz, 1H), 7.55-7.48 (m, 1H), 7.01-6.94 (m, 2H), 6.83-6.78 (m, 2H), 4.18 (t, J=5.7 Hz, 2H), 3.91-3.84 (m, 5H), 3.26 (s, 3H), 1.36 (s, 9H); ESI MS m/z 403 [M+H]⁺.

Step B: To a solution of methyl 2-(3-(2-(2-(tert-butyl)-4-fluorophenoxy)ethyl)-3-methylureido)benzoate (0.110 g, 0.273 mmol) in THF (5.4 mL) and CH₂OH (2.8 mL) was added a solution of LiOH.H₂O (0.114 g, 2.73 mmol) in H₂O (1.4 mL). The mixture stirred at room temperature for 18 hours, was acidified with 2 N HCl, and diluted with H₂O (30 mL). The resulting solids were collected by filtration and washed with H₂O to provide 2-(3-(2-(2-(tert-butyl)-4-fluorophenoxy)ethyl)-3-methylureido)benzoic acid as a white solid (99 mg, 93%): mp 145-150° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.51 (s, 1H), 10.94 (s, 1H), 8.47 (d, J=8.5 Hz, 1H), 7.95 (dd, J=8.0, 1.5 Hz, 1H), 7.55-7.49 (m, 1H), 7.03-6.93 (m, 4H), 4.14 (t, J=5.5 Hz, 2H), 3.80 (t, J=6.0 Hz, 2H), 3.10 (s, 3H), 1.26 (s, 9H); ESI MS m/z 389 [M+H]⁺.

Example 18: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-5-(methylsulfonyl)-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide (28)

Step A: Following general procedure GP-I, N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide hydrochloride and methanesulfonyl chloride were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-5-(methylsulfonyl)-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide as a white solid (30 mg, 40%): mp 125-133° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.44-13.18 (m, 1H), 7.23-7.10 (m, 2H), 7.73-7.69 (m, 1H), 6.89-6.82 (m, 1H), 4.56-4.36 (m, 4H), 4.26-4.14 (m, 2H), 3.93-3.86 (m, 1.5H), 3.51 (s, 0.5H), 3.29-3.25 (s, 1H), 3.22-3.16 (m, 1H), 3.07-2.96 (m, 4H), 1.34-1.14 (m, 9H); ESI MS m/z 421 [M+H]⁺.

Example 19: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N,5-dimethyl-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide (29)

Step A: Following general procedure GP-J, M-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide hydrochloride and formaldehyde were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N,5-dimethyl-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide as a white solid (20 mg, 15%): ¹H NMR (500 MHz, DMSO-d₆) δ12.99 (s, 1H), 7.22-7.11 (m, 2H), 7.03-6.93 (m, 1H), 6.89-6.82 (m, 1H), 4.44-3.31 (m, 9H), 3.26-2.93 (m, 3H), 1.36-1.13 (m, 9H); ESI MS m/z 357 [M+H]⁺.

Example 20: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-5-(methylsulfonyl)-4,5,5,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide (30)

Step A: Following general procedure GP-C, N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide hydrochloride and methanesulfonyl chloride were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-5-(methylsulfonyl)-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide as a white solid (34 mg, 46%): mp 226-230° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.04 (s, 1H), 7.23-7.12 (m, 2H), 7.35 (dd, J=17.5, 7.5 Hz, 1H), 6.85 (dd, J=14.5, 7.5 Hz, 1H), 4.44 (t, J=6.0 Hz, 1H), 4.34 (d, J=8.5 Hz, 2H), 4.23-4.17 (m, 2H), 3.89 (t, J=5.5 Hz, 1H), 3.52-3.42 (m, 3.3H), 3.05 (s, 1.7H), 2.92 (s, 3H), 2.85-2.78 (m, 2H), 1.32-1.19 (m, 9H); ESI MS m/z 435 [M+H]⁺.

Example 21: Preparation of 5-acetyl-N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide (31)

Step A: Following general procedure GP-B, N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide hydrochloride and acetyl chloride were combined to give 5-acetyl-N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine-3-carboxamide as a white solid (42 mg, 69%): ¹H NMR (500 MHz, DMSO-d₆) δ 13.00-12.92 (m, 1H), 7.23-7.11 (m, 2H), 7.04-6.95 (m, 1H), 6.89-6.81 (m, 1H), 4.56-4.51 (m, 2H), 4.46-4.37 (m, 1H), 4.24-4.15 (m, 2H), 3.92-3.85 (m, 1H), 3.74-3.69 (m, 1H), 3.67-3.60 (m, 1H), 3.53-3.43 (m, 1H), 3.30-3.27 (m, 1H), 3.07-3.03 (m, 1H), 2.79-2.72 (m, 1H), 2.67-2.60 (m, 1H), 2.10-2.01 (m, 3H), 1.34-1.20 (m, 9H); ESI MS m/z 399 [M+H]⁺.

Example 22: Preparation of 6-Acetyl-N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide (32)

Step A: Following general procedure GP-E, N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide hydrochloride and acetyl chloride were combined to give 6-acetyl-N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide as a white solid (28 mg, 55%): ¹H NMR (500 MHz, DMSO-d₆) δ 13.00-12.91 (m, 1H), 7.23-7.10 (m, 2H), 7.03-6.95 (m, 1H), 6.89-6.82 (m, 1H), 4.54 (s, 2H), 4.46-4.37 (m, 1H), 4.22-4.18 (m, 2H), 3.91-3.86 (m, 1H), 3.73-3.69 (m, 1H), 3.66-3.61 (m, 1H), 3.52-3.45 (m, 1H), 3.07-3.02 (m, 2H), 2.79-2.71 (m, 1H), 2.66-2.60 (m, 1H), 2.09-2.01 (m, 3H), 1.33-1.19 (m, 9H); ESI MS m/z 399 [M+H]⁺.

Example 23: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N-methyl-6-(methylsulfonyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide (33)

Step A: Following general procedure GP-F, N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide hydrochloride and methanesulfonyl chloride were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-6-(methylsulfonyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide as a white solid (23 mg, 42%): mp 233-237° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 13.04 (s, 1H), 7.22-7.12 (m, 2H), 7.03-6.94 (m, 1H), 6.88-6.82 (m, 1H), 4.44 (t, J=6.0 Hz, 1H), 4.36-4.32 (m, 2H), 4.22-4.17 (m, 2H), 3.89 (t, J=5.5 Hz, 1H), 3.49 (s, 1H), 3.47-3.42 (m, 2H), 3.05 (s, 2H), 2.92 (s, 3H), 2.84-2.77 (m, 2H), 1.30 (s, 4H) 1.21 (s, 5H); ESI MS m/z 435 [M+H]⁺.

Example 24: Preparation of N-(2-(2-(Tert-butyl)phenoxy)ethyl)-N,6-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide (34)

Step A: Following general procedure GP-G, N-(2-(2-(tert-butyl)phenoxy)ethyl)-N-methyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide hydrochloride and formaldehyde were combined to give N-(2-(2-(tert-butyl)phenoxy)ethyl)-N,6-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide as a white solid (30 mg, 34%): mp 159-161° C.; ¹H NMR (500 MHz, DMSO-d₆) δ 12.79 (s, 1H), 7.23-7.09 (m, 2H), 7.04-6.94 (m, 1H), 6.89-6.81 (m, 1H), 4.35 (t, J=6.0 Hz, 1H), 4.22-4.16 (m, 2H), 3.86 (t, J=5.5 Hz, 1H), 3.45-3.38 (m, 3H), 3.03 (s, 2H), 2.70-2.63 (m, 2H), 2.62-2.56 (m, 2H), 2.34 (s, 3H), 1.37-1.30 (m, 9H); ESI MS m/z 371 [M+H]⁺.

Example 25: Preparation of N-(2-(3,5-bis(trifluoromethyl) phenoxy)ethyl)-N-methyl-6,13-dihydro-5H-[1,2,4]triazolo[3,4-c][1,4]oxazine-3-carboxamide (35)

The above compound is prepared by similar methods as those used to prepare compound 25 except that 3,5-bis(trifluoromethyl)phenol is used in place of 2-tert-butylphenol.

Example 26: Preparation of methyl 2-((2-(2-(tart-butyl)phenoxy) ethyl)(methyl)amino)-6-methylpyrimidine-4-carboxylate (36)

The above compound is prepared by similar methods as those used to described hereinabove except that methyl amine 4 is used as nucleophile to, in the presence of triethylamine, directly displace the chlorine of methyl 2-chloro-6-methylpyrimidine-4-carboxylate.

Example 27: Preparation of 2-((2-(2-(tert-butyl)phenoxy)ethyl) (methyl)amino)-6-methylpyrimidine-4-carboxylic acid (37)

The above compound is prepared by hydrolyzing the ester of compound 36 under basic conditions.

Example 28: Preparation methyl 2-((2-(3,5-bis(trifluoromethyl) phenoxy)ethyl)(methyl)amino)-6-methylpyrimidine-4-carboxylate (38)

The above compound is prepared by similar methods as those used to described hereinabove for compound 36 except that the 3,5-bis(trifluoromethyl) derivative of methyl amine 4 is used.

Example 29: Preparation of 2-((2-(3,5-bis(trifluoromethyl) phenoxy) ethyl)(methyl)amino)-6-methylpyrimidine-4-carboxylic acid (39)

The above compound is prepared by hydrolyzing the ester of compound 38 under basic conditions.

Example 30: RPB4 Binding of N-Alkyl Amide Compounds

Various compounds listed in Examples 1-24 (compounds 11-14 and 19-34) were tested in two in vitro assays, RBP4 binding (SPA) and retinol-dependent RBP4-TTR interaction (HTRF) (FIG. 8). The compounds binded to RBP4 and/or antagonized retinol-dependent RBP4-TTR interaction. This activity indicates that the compounds reduce the levels of serum RBP4 and retinol.

Example 31: APES Binding of Additional N-Alkyl Amide Compounds

An additional aspect of the invention provides analogs of the compounds of Examples 1-24 that are active as RBP4 antagonists. The analogs of Examples 1-24 described herein analogously bind to RBP4 and antagonize retinol-dependent RBP4-TTR interaction.

Compounds 36, 37, 38, and 39, which are analogs of those described in Example 1-24, are tested in two in vitro assays. RBP4 binding (SPA) and retinol-dependent RBP4-TTR interaction (HTRF). These compounds bind to RBP4 and antagonize retinol-dependent RBP4-TTR interaction. This activity indicates that the compounds reduce the level of serum RBP4 and retinol.

Additional N-alkyl amide compounds, which are analogs of those described in Example 1-24, are tested in two in vitro assays, RBP4 binding (SPA) and retinol-dependent RBP4-TTR interaction (HTRF). These compounds bind to RBP4 and antagonize retinol-dependent RBP4-TTR interaction. This activity indicates that the compounds reduce the level of serum RBP4 and retinol.

Additional N-methyl amide compounds, which are analogs of those described in Example 1-24, are tested in two in vitro assays, RBP4 binding (SPA) and retinol-dependent RBP4-TTR interaction (HTRF). These compounds bind to RBP4 and antagonize retinol-dependent RBP4-TTR interaction. This activity indicates that the compounds reduce the level of serum RBP4 and retinal.

Example 32: Efficacy in a Mammalian Model

The effectiveness of the compounds listed in Example 1-24 are tested in wild-type and Abca4−/− mice. The Abca4−/− mouse model manifests accelerated accumulation of lipofuscin in the RPE and is considered a pre-clinical efficacy model for a drug reducing lipofuscin accumulation. Compounds are orally dosed for 3 weeks at 30 mg/kg. There is a reduction in the serum RBP4 level in treated animals. The levels of A2E/isoA2E and other bisretinoids are reduced in treated mice. The levels of A2-DHP-PE and atRAL di-PE are also reduced.

The effectiveness of additional N-alkyl amide compounds, which are analogs of those described in Examples 1-46, are tested in wild-type and Abca4−/− mice. The Abca4−/− mouse model manifests accelerated accumulation of lipofuscin in the RPE and is considered a pre-clinical efficacy model for a drug reducing lipofuscin accumulation. Compounds are orally dosed for 3 weeks at 30 mg/kg. There is s reduction in the serum RBP4 level in treated animals. The levels of A2E/isoA2E and other bisretinoids are reduced in treated mice. The levels of A2-DHP-PE and atRAL di-PE are also reduced.

The effectiveness of additional N-methyl amide compounds, which are analogs of those described in Examples 1-46, are tested in wild-type and Abca4−/− mice. The Abca4−/− mouse model manifests accelerated accumulation of lipofuscin in the RPE and is considered a pre-clinical efficacy model for a drug reducing lipofuscin accumulation. Compounds are orally dosed for 3 weeks at 30 mg/kg. There is s reduction in the serum RBP4 level in treated animals. The levels of A2E/isoA2E and other bisretinoids are reduced in treated mice. The levels of A2-DHP-PE and atRAL di-PE are also reduced.

Discussion

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. Its prevalence is higher than that of Alzheimer's disease. There is no treatment for the most common dry form of AMD. Dry AMD is triggered by abnormalities in the retinal pigment epithelium (RPE) that lies beneath the photoreceptor cells and provides critical metabolic support to these light-sensing cells. RPE dysfunction induces secondary degeneration of photoreceptors in the central part of the retina called the macula. Experimental data indicate that high levels of lipofuscin induce degeneration of RPE and the adjacent photoreceptors in atrophic AMD retinas. In addition to AMD dramatic accumulation of lipofuscin is the hallmark of Stargardt's disease (STGD), an inherited form of juvenile onset macular degeneration. The major cytotoxic component of RPE lipofuscin is a pyridinium bisretinoid A2E. A2E formation occurs in the retina in a non-enzymatic manner and can be considered a by-product of a properly functioning visual cycle. Given the established cytotoxic affects of A2E on RPE and photoreceptors, inhibition of A2E formation could lead to delay in visual loss in patients with dry AMD and STGD. It was suggested that small molecule visual cycle inhibitors may reduce the formation of A2E in the retina and prolong RPE and photoreceptor survival in patients with dry AMD and STGD. Rates of the visual cycle and A2E production in the retina depend on the influx of all-trans retinol from serum to the RPE. RPE retinol uptake depends on serum retinol concentrations. Pharmacological downregulation of serum retinol is a valid treatment strategy for dry AMD and STGD. Serum retinol is maintained in circulation as a tertiary complex with retinol-binding protein (RBP4) and transthyretin (TTR). Without interacting with TTR, the RBP4-retinol complex is rapidly cleared due to glomerular filtration. Retinal binding to RBP4 is required for formation of the RBP4-TTR complex; apo-RBP4 does not interact with TTR. Importantly, the retinol-binding site on RBP4 is sterically proximal to the interface mediating the RBP4-TTR interaction. Without wishing to be bound by any scientific theory, the data herein show that small molecule RBP4 antagonists displacing retinol from RBP4 and disrupting the RBP4-TTR interaction will reduce serum retinol concentration, inhibit retinal uptake into the retina and act as indirect visual cycle inhibitors reducing formation of cytotoxic A2E.

Serum RBP4 as a Drug Target for Pharmacological Inhibition of the Visual Cycle

As rates of the visual cycle and A2E production in the retina depend on the influx of all-trans retinol from serum to the RPE (FIG. 4), it has been suggested that partial pharmacological down-regulation of serum retinol may represent a target area in dry AMD treatment (11). Serum retinol is bound to retinol-binding protein (RBP4) and maintained in circulation as a tertiary complex with RBP4 and transthyretin (TTR) (FIG. 5). Without interacting with TTR, the RBP4-retinol complex is rapidly cleared from circulation due to glomerular filtration. Additionally, formation of the RBP4-TTR-retinol complex is required for receptor-mediated all-trans retinol uptake from serum to the retina.

Without wishing to be bound by any scientific theory, visual cycle inhibitors may reduce the formation of toxic bisretinoids and prolong RPE and photoreceptor survival in dry AMD. Rates of the visual cycle and A2E production depend on the influx of all-trans retinol from serum to the RPE. Formation of the tertiary retinol-binding protein 4 (RBP4)-transthyretin (TTR)-retinol complex in serum is required for retinol uptake from circulation to the RPE. Retinol-binding site on RBP4 is sterically proximal to the interface mediating the RBP4-TTR interaction. RBP4 antagonists that compete with serum retinol for binding to RBP4 while blocking the RBP4-TTR interaction would reduce serum retinol, slow down the visual cycle, and inhibit formation of cytotoxic bisretinoids.

RBP4 represents an attractive drug target for indirect pharmacological inhibition of the visual cycle and A2E formation. The retinol-binding site on RBP4 is sterically proximal to the interface mediating the RBP4-TTR interaction. Retinol antagonists competing with serum retinal for binding to RBP4 while blocking the RBP4-TTR interaction would reduce serum RBP4 and retinol levels which would lead to reduced uptake of retinol to the retina. The outcome would be visual cycle inhibition with subsequent reduction in the A2E synthesis.

A synthetic retinoid called fenretinide [N-(4-hydroxy-phenyl)retinamide, 4HRP] (FIG. 6) previously considered as a cancer treatment (29) was found to bind to RBP4, displace all-trans retinol from RBP4 (13), and disrupt the RBP4-TTR interaction (13,14).

Fenretinide was shown to reduce serum RBP4 and retinol (15), inhibit ocular all-trans retinal uptake and slow down the visual cycle (11). Importantly, fenretinide administration reduced A2E production in an animal model of excessive bisretinoid accumulation, Abca4−/− mice (11). Pre-clinical experiments with fenretinide validated RBP4 as a drug target for dry AMD. However, fenretinide is non-selective and toxic. Independent of its activity as an antagonist of retinal binding to RBP4, fenretinide is an extremely active inducer of apoptosis in many cell types (16-19), including the retinal pigment epithelium cells (20). It has been suggested that fenretinide's adverse effects are mediated by its action as a ligand of a nuclear receptor RAR (21-24). Additionally, similar to other retinoids, fenretinide is reported to stimulate formation of hemangiosarcomas in mice. Moreover, fenretinide is teratogenic, which makes its use problematic in Stargardt disease patients of childbearing age.

As fenretinide's safety profile may be incompatible with long-term dosing in individuals with blinding but non-life threatening conditions, identification of new classes of RBP4 antagonists is of significant importance. The compounds of the present invention displace retinol from RBP4, disrupt retinol-induced RBP4-TTR interaction, and reduce serum REBP4 levels. The compounds of the present invention inhibit bisretinoid accumulation in the Abca4−/− mouse model of excessive lipofuscinogenesis which indicates usefulness a treatment for dry AMD and Stargardt disease.

The present invention relates to small molecules for treatment of macular degeneration and Stargardt Disease. Disclosed herein is the ophthalmic use of the small molecule as non-retinoid RBP4 antagonists. The compounds of Examples 1-24 have been shown to bind RBP4 in vitro and/or to antagonize RBP4-TTR interaction in vitro at biologically significant concentrations. Additional compounds described herein, which are analogs of Examples 1-24 analogously bind RBP4 in vitro and antagonize RBP4-TTR interaction in vitro at biologically significant concentrations. Compounds 36, 37, 38, and 39, which are analogs of Examples 1-24 analogously bind RBP4 in vitro and antagonize RBP4-TTR interaction in vitro at biologically significant concentrations.

Currently, there is no FDA-approved treatment for dry AMD or Stargardt disease, which affects millions of patients. An over the counter, non FDA-approved cocktail of antioxidant vitamins and zinc (AREDS formula) is claimed to be beneficial in a subset of dry AMD patients. There are no treatments for Stargardt disease. The present invention identified non-retinoid RBP4 antagonists that are useful for the treatment of dry AMD and other conditions characterized by excessive accumulation of lipofuscin. Without wishing to be bound by any scientific theory, as accumulation of lipofuscin seems to be a direct cause of RPE and photoreceoptor demise in AMD and STGD retina, the compounds described herein are disease-modifying agents since they directly address the root cause of these diseases. The present invention provides novel methods of treatment that will preserve vision in AMD and Stargardt disease patients, and patients' suffering from conditions characterized by excessive accumulation of lipofuscin.

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What is claimed is:
 1. A compound having the structure:

wherein R₁, R₂, R₃ and R₄ are each independently H, halogen, CF₃ or C₁-C₄ alkyl, and R₅ is CF₃, t-butyl, propyl or isopropyl; R₆ is alkyl; A is absent or present, and when present is

and B has the structure:

wherein R₁₀ is H, C₁-C₁₀ alkyl, C₃-C₆ cycloalkyl, (C₁-C₁₀ alkyl)-CF₃, (C₁-C₁₀ alkyl)-OCH₃, (C₁-C₁₀ alkyl)-halogen, SO₂—(C₁-C₁₀ alkyl), SO₂—(C₁-C₁₀ alkyl)-CF₃, SO₂—(C₁-C₁₀ alkyl)-OCH₃, SO₂—(C₁-C₁₀ alkyl)-halogen, C(O)—(C₁-C₁₀ alkyl), C(O)—(C₁-C₁₀ alkyl)-CF₃, C(O)—(C₁-C₁₀ alkyl)-OCH₃, C(O)—(C₁-C₁₀ alkyl)-halogen, C(O)—NH—(C₁-C₁₀ alkyl), C(O)—N(C₁-C₄ alkyl)₂, (C₁-C₁₀ alkyl)-C(O)OH, C(O)—NH₂ or oxetane,

wherein R₇ is H, C₁-C₄ alkyl, or oxetane; and Y₁, Y₂, Y₃ and Y₄ are each independently CR₈ or N, wherein each R₈ is independently H, halogen, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, O—(C₁-C₄ alkyl), C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃, NHC(O)—N(CH₃)₂, CN, or CF₃, or a pharmaceutically acceptable salt thereof.
 2. The compound of claim 1 having the structure:


3. The compound of claim 1, wherein B has the structure:


4. The compound of claim 1, wherein B has the structure:


5. The compound of claim 1, wherein B has the structure:

wherein R₇ is H, C₁-C₄ alkyl, or oxetane; and Y₁, Y₂, Y₃ and Y₄ are each independently CR₈ or N, wherein each R₈ is independently H, halogen, C₁-C₄ alkyl, C₁-C₄ cycloalkyl, O—(C₁-C₄ alkyl), C(O)OH, C(O)—NH₂, C(O)—N(CH₃)₂, C(O)—NHCH₃, NHC(O)—N(CH₃)₂, CN, or CF₃.
 6. The compound of claim 1 having the structure:

or a pharmaceutically acceptable salt thereof.
 7. A pharmaceutical composition comprising the compound of claim 1 and a pharmaceutically acceptable carrier.
 8. A method for treating a disease characterized by excessive lipofuscin accumulation in the retina in a mammal afflicted therewith comprising administering to the mammal an effective amount of the compound of claim
 1. 9. The compound claim 1, wherein R₁, R₂, R₃ and R₄ are each H; and R₅ is CF₃, t-Bu or i-Pr.
 10. The compound of claim 1, wherein R₆ is methyl. 